Zdenek,
I'm not sure what you mean by the "VISA interactive control". I put together a little VI that uses the VISA sub VIs to ask this question of my instrument, and I would have attached the VI and the NISpy capture files below but experienced technical problems with my browser. In any case, there was no problem with the low-level Visa queries (viWriteAsync, viReadAsync) that resulted.
MAX reports that NI-VISA is version 3.1, with all the individual DLL version numbers listed separately. e.g. visa32.dll is 3.1.0.24, while NiVi488.dll is 3.1.0.35.
Very many thanks for your help with this problem.
Best regards,
Nick