PCI 6601 counter - resource reserved while debugging in Visual Studio

Hi,

I'm trying to debug an application which uses counter1 on the PCI 6601 bord to create a continous pulse train. The application is in VB and with Visual Studio 2012 I always get the Error: -50103 specified recource is reserved. This error occurs right after the application is loaded to VS, so no task is created at that time. Has anybody experienced a similar behaviour?

I would be thankful for any ideas.

Thanks in advance