Are you using the standard C library of NI-FBUS CM or Borland C library? The NI-FBUS CM 3.0 and later version (like 3.1) do not support Borland C library; but it supports standard C and Visual C++.
In addition, the 3.0 version has API changes, some structures are different from previous version (like 2.3, 2.3.5 and 2.3.6), you need to re-compile your program with the new 3.0 library to make it work with NI-FBUS CM server.
If it still doesn't help, try to send e-mail to fieldbus.support@ni.com for NI e-mail support.
