No access to network files in Paradox 7 for win 95

I am using Paradox (the programm) on local machines, the tables and forms
etc on a Banyan Vines Network (6.30, including patches for win95 PC's and
new client software).
In a form showing persons, a user can click on a button to open another
small form, to search for a specific person. In this new small form, the
user types a part of the name and clickt on a OK-button to start the
search. So far so good, but after some 30 / 40 searches, Paradox refuses to
open the search form again. And when you go to the design mode, Paradox
doesn't see any file anymore on the network directory!!! HELP!!!!
I tested the same forms and tables in Paradox 5.0 and this version doesn't
seem to have this problem.
I already installed bugfix 4.
Also with all the files (tables, formes etc) on my local PC, this problem
doesn't occur!!!

The first error message I get is:
        You have tried to access a document that is not open

Is this a bug??? Please help!!!  To: