Problem with ODBC connection Navision/SQL Server 2005

Hello,

I have created a SSIS package which copies data from Navision 3.70 database to SQL Server 2005. I'm using C/ODBC driver 3.70. DNS is set up, connection test in SSIS package Connection Manager says ok. Data Reader Source of SSIS Data Flow Task says when being executed:

SSIS package "Package.dtsx" starting.
Information: 0x4004300A at test, DTS.Pipeline: Validation phase is beginning.
Error: 0xC0047062 at test, DataReader Source [379]: System.Data.Odbc.OdbcException: ERROR [IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
   at Microsoft.SqlServer.Dts.Runtime.Wrapper.IDTSConnectionManager90.AcquireConnection(Object pTransaction)
   at Microsoft.SqlServer.Dts.Pipeline.DataReaderSourceAdapter.AcquireConnections(Object transaction)
   at Microsoft.SqlServer.Dts.Pipeline.ManagedComponentHost.HostAcquireConnections(IDTSManagedComponentWrapper90 wrapper, Object transaction)
Error: 0xC0047017 at test, DTS.Pipeline: component "DataReader Source" (379) failed validation and returned error code 0x80131937.
Error: 0xC004700C at test, DTS.Pipeline: One or more component failed validation.
Error: 0xC0024107 at test: There were errors during task validation.
SSIS package "Package.dtsx" finished: Success.

Any idea what's going wrong here?

Thanks
Michael