SQL Server 2005 Timeout expired exception

Hi,

I have a program in C# that I used to run on Visual Studio 2000 and SQL Server 2000 without any problem.

Now I upgrade to VS2005 and SQL Server 2005 and get and exception while

insert via SqlCommand.ExecuteNonQuery(). the insert is after many inserts to the same table by that program. the CommandTimeout is set to 600 (in the 2000 version I never had to change the default value of 30 seconds).

the insert is through a connection that is kept open throughout the program for more than 30 minutes

the exception message is:

Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

the trace is:

   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
   at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()

Thanks for your help !