Interbase: Unreliable Network Connection

Does anyone know what would cause the following error:

General SQL Error.
Unable to complete network request to host "Lee".
Error writing data to the connection.
Unknown Win32 error 10054.

A user will be running queries with out a problem when all of a sudden this
message will pop up.

What would cause the system to work fine one minute and hiccup the next??

One additional note... This even occurs if you run the program from the NT
station being used as the Server!

Here are the system stats:
D3.02/IB5.0 on NT/Connected via a NetWare Network

This is driving me crazy!!

Thanks,
Rea