One user of my product is reporting severe problems when accessing the
software from Netware 5 server (via UNC mapping). Customer has the
official Vista client installed.

Their NW 5 server seem to drop open file connections after 20-25 concurrent
users are accessing our software. Each instance of software keeps open a few
small files from the shared directory on NW server, nothing unusual, but now
the file handles seem to die .

Any ideas, how could we debug more what is causing this? Could it be some
incompatibility with Vista and NW5 server?