Error al crear una nueva categoría de puesto en Evolution

Al intentar crear un nuevo registro de Categoría de puestos en Evolution aparece el siguiente mensaje de error: Error en el sistema Se ha producido un inconveniente... La acción 'Create' del controlador 'CategoriaPuesto' ha lanzado la excepción 'DuplicateKeyException' con el mensaje: Se trató de insertar una entidad que ya existe (key=[Codigo, 0]). Favor revisar los valores de la entidad.

Pensé que el problema podía ser el identity, pero al probar insertar un registro directamente en la tabla no tuve problemas.

Coloco el resultado que en Elmah aparece:

{ "host": "EVOAPPDEV", "type": "Aseinfo.Infrastructure.Base.Exceptions.DuplicateKeyException", "message": "Se trató de insertar una entidad que ya existe 
(key=[Codigo, 0]). Favor revisar los valores de la entidad.", "source": "Aseinfo.Infrastructure.Base", "detail": 
"Aseinfo.Infrastructure.Base.Exceptions.DuplicateKeyException: Se trató de insertar una entidad que ya existe (key=[Codigo, 0]). Favor revisar los valores de 
la entidad.\r\n   at Aseinfo.Infrastructure.Base.Entity.GenericEntityRepository.InsertWithoutSavingChanges[T](T entity) in 
c:\\VH4\\Infrastructure\\Base\\Entity\\GenericEntityRepository.cs:line 152\r\n   at Aseinfo.Infrastructure.Base.Entity.EntityServiceBase`2.DoInsert(T entity, 
Boolean saveChanges, Boolean bypassWorkflowInitialization) in c:\\VH4\\Infrastructure\\Base\\Entity\\EntityServiceBase.cs:line 816\r\n   at 
Aseinfo.VH4.Estructura.Controllers.CategoriaPuestoController.SaveCategoriaPuesto(CategoriaPuesto entity, Nullable`1 codigoClasificacion, Int32 
codigoGrupoCorporativo, Boolean inserting) in c:\\BuildAgent\\work\\608d469cc106b504\\VH4\\Estructura\\Controllers\\CategoriaPuestoController.cs:line 237\r\n   
at Aseinfo.VH4.Estructura.Controllers.CategoriaPuestoController.Create(CategoriaPuesto entity, Nullable`1 codigoClasificacion, Int32 codigoGrupoCorporativo) in 
c:\\BuildAgent\\work\\608d469cc106b504\\VH4\\Estructura\\Controllers\\CategoriaPuestoController.cs:line 127\r\n   at lambda_method(Closure , ControllerBase , 
Object[] )\r\n   at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)\r\n   at 
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 
parameters)\r\n   at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()\r\n   at 
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)\r\n   at 
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)\r\n   at 
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)\r\n   at 
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, 
IDictionary`2 parameters)\r\n   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)", "user": 
"admin", "time": "2015-05-21T20:29:18.0894156Z", "serverVariables": { "ALL_HTTP": 
"HTTP_CACHE_CONTROL:max-age=0\r\nHTTP_CONNECTION:keep-alive\r\nHTTP_CONTENT_LENGTH:394\r\nHTTP_CONTENT_TYPE:application/x-www-form-urlencoded\r\nHTTP_ACCEPT:text
/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\nHTTP_ACCEPT_ENCODING:gzip, 
deflate\r\nHTTP_ACCEPT_LANGUAGE:es-ES,es;q=0.8\r\nHTTP_COOKIE:ASP.NET_SessionId=dfy2cjgcjm2yyxkydsytzvf2; 
__RequestVerificationToken_L0V2b2x1dGlvbg__=uUXKclQGZ7pz8tYcvm99PplWIIg/EpbI9+1ru3SEQq+4B55rI7HcCV2G9+WOWlRza17cfsEOvb9Vhooq2klEriPNA3+VzepFWoVKkCuAx9R3WifFuk7uj
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UsernameCookieKey=\r\nHTTP_HOST:localhost\r\nHTTP_REFERER:http://localhost/Evolution/Estructura/CategoriaPuesto/Create\r\nHTTP_USER_AGENT:Mozilla/5.0 (Windows 
NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.65 Safari/537.36\r\nHTTP_ORIGIN:http://localhost\r\n", "ALL_RAW": "Cache-Control: 
max-age=0\r\nConnection: keep-alive\r\nContent-Length: 394\r\nContent-Type: application/x-www-form-urlencoded\r\nAccept: 
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\nAccept-Encoding: gzip, deflate\r\nAccept-Language: es-ES,es;q=0.8\r\nCookie: 
ASP.NET_SessionId=dfy2cjgcjm2yyxkydsytzvf2; 
__RequestVerificationToken_L0V2b2x1dGlvbg__=uUXKclQGZ7pz8tYcvm99PplWIIg/EpbI9+1ru3SEQq+4B55rI7HcCV2G9+WOWlRza17cfsEOvb9Vhooq2klEriPNA3+VzepFWoVKkCuAx9R3WifFuk7uj
gk5ZLKpP7fe1c+2l7GIJwWJYj/WYb8XrQ/W422aITqG6Ng/ZXS5FII=; 
.ASPXFORMSAUTH=9531B90D9AB19DEA3BA47BC1B6C4A0367FCF81E9BA26A0037D5E5BF2A01A0FF49B23100B40CA8EB5B3CCC60E94C1437753B6A652728D2AE00F4BEEDAFBC2955CE52E5F7B69DE80B29E
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localhost\r\nReferer: http://localhost/Evolution/Estructura/CategoriaPuesto/Create\r\nUser-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 
(KHTML, like Gecko) Chrome/43.0.2357.65 Safari/537.36\r\nOrigin: http://localhost\r\n", "APPL_MD_PATH": "/LM/W3SVC/1/ROOT/Evolution", "APPL_PHYSICAL_PATH": 
"C:\\inetpub\\wwwroot\\Evolution\\", "AUTH_TYPE": "Forms", "AUTH_USER": "admin", "LOGON_USER": "admin", "REMOTE_USER": "admin", "CONTENT_LENGTH": "394", 
"CONTENT_TYPE": "application/x-www-form-urlencoded", "GATEWAY_INTERFACE": "CGI/1.1", "HTTPS": "off", "INSTANCE_ID": "1", "INSTANCE_META_PATH": "/LM/W3SVC/1", 
"LOCAL_ADDR": "::1", "PATH_INFO": "/Evolution/Estructura/CategoriaPuesto/Create", "PATH_TRANSLATED": 
"C:\\inetpub\\wwwroot\\Evolution\\Estructura\\CategoriaPuesto\\Create", "REMOTE_ADDR": "::1", "REMOTE_HOST": "::1", "REMOTE_PORT": "55998", "REQUEST_METHOD": 
"POST", "SCRIPT_NAME": "/Evolution/Estructura/CategoriaPuesto/Create", "SERVER_NAME": "localhost", "SERVER_PORT": "80", "SERVER_PORT_SECURE": "0", 
"SERVER_PROTOCOL": "HTTP/1.1", "SERVER_SOFTWARE": "Microsoft-IIS/7.5", "URL": "/Evolution/Estructura/CategoriaPuesto/Create", "HTTP_CACHE_CONTROL": 
"max-age=0", "HTTP_CONNECTION": "keep-alive", "HTTP_CONTENT_LENGTH": "394", "HTTP_CONTENT_TYPE": "application/x-www-form-urlencoded", "HTTP_ACCEPT": 
"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8", "HTTP_ACCEPT_ENCODING": "gzip, deflate", "HTTP_ACCEPT_LANGUAGE": 
"es-ES,es;q=0.8", "HTTP_COOKIE": "ASP.NET_SessionId=dfy2cjgcjm2yyxkydsytzvf2; 
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gk5ZLKpP7fe1c+2l7GIJwWJYj/WYb8XrQ/W422aITqG6Ng/ZXS5FII=; 
.ASPXFORMSAUTH=9531B90D9AB19DEA3BA47BC1B6C4A0367FCF81E9BA26A0037D5E5BF2A01A0FF49B23100B40CA8EB5B3CCC60E94C1437753B6A652728D2AE00F4BEEDAFBC2955CE52E5F7B69DE80B29E
3D6A4AF21403BB1936D8FB5B1835300EB6215EC53F134C04BA6EE6954EAB81C648928D805051508520DE7737ECF41EEA6D87D80BA95F72; UsernameCookieKey=", "HTTP_HOST": "localhost", 
"HTTP_REFERER": "http://localhost/Evolution/Estructura/CategoriaPuesto/Create", "HTTP_USER_AGENT": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 
(KHTML, like Gecko) Chrome/43.0.2357.65 Safari/537.36", "HTTP_ORIGIN": "http://localhost" }, "form": { "__RequestVerificationToken": 
"aNvu9u01n485llyahrscj1CYtalZfmZuqVG1oa2hv8NDd8ATnC2PxRPEbFvUMuKXQDsAtZcOir3r9bwodph9BnFpf+h2oNQ2MNznEqBP75YTWekTXlJi4dD/0UFrERUN7LPvwpHK0v7dIFubS3g21rLFsE64oo8o
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"CodigoClasificacion": "9", "codigoGrupoCorporativo": "1" }, "cookies": { "ASP.NET_SessionId": "dfy2cjgcjm2yyxkydsytzvf2", 
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