Problem:

Isam files at client's site were getting corrupted.  Some of the files used are large, 1Gb

Resolution:

The resolution to the problem was to turn the opportunistic looking setting on the Novell server to OFF.

Suggestions:

1) Ensure that the Novell Opportunistic Locking setting is turned OFF

2) Add READSEMA=OFF to your current EXTFH.CFG

3) No regular maintenance is done on the ISAM files.  Made the strong suggestion that they reorg the files on a regular basis.