I've got the same problem in FPW 2.6. The problem seems to be a lost connection to the file server. The workstation opens only a small amount of a table. When it requests a bigger portion of the table it asks the server for more data. But when he server has shutdown the file-connection. The workstation ends up with a illegal offset or other simmular messages.

One major cause of this problem is the suspend option under windows 95. When a Workstation goes into suspend mode it disconnect the connection with all files and tries to reconnect at a wakeup. The workstation is able to reconnect to the file because of some multiusers reasons at the server side.

I suggest to check if the problem is the Suspend mode. If not, it could be the configuration of the server. If it is a NT-server just mail me, I have some information which could help you out