The full error message is:
Internal operating system error
File: file path and file name

System information:
Delphi 7, BDE 5.01, Paradox 7
2 Win Vista Business

BDE <Net Dir> is in a shared folder C:\PdoxNet
The program is in a shared folder C:\Prog
Permission are given to the users as full control on those two folders.

The above error pops up intermittently at very different places in the program. It may not happen for hours, it may happen within minutes of entering the program.
After the error, the program freeze.
File path and file name always shows a pdox 7 table that is relevant in the program context. Since the error can occur in any context, any table of the application, small or large, has shown up at one time or another.
There is never any damage to any table. The error cannot be acknowledged, the program is stopped by end process. It can be reentered right away, and it will be impossible to recreate the error. It will happen again, but in another place in another context.
with just one user their no problem in the system. when the second user open the program for sure the message will appear on one station and the other station need a reboot not even the end process works.
Help is greatly appreciated.

have you gone thru all the normal stuff.. local share, oplocks, caching, etc? have you rebuilt the tables and indexes, then packed them, recently (not just Verify)? are any of your main tables getting much larger than previosly expected? have you blown away all the lock and net files? have you checked the network connections?.. even "random" will eventually have a root cause..

thanks for your reply,
i have passed all the normal stuff except for oplock,
by the way i have no problems with the 2003 server or XP or any other windows flavors; my only problems happen with vista and only when multiple users access the data simultaneously.

regards