вот похоже на твою проблему:

NET file - file that BDE uses to control sharing/access/user rights to
tables. Should live in a directory that is reachable from all apps that use
Paradox tables, usually a shared network directory.

LCK file - one of two LCK files created in the directory(ies) in which
shared tables are accessed. These control the locking of tables/records in
that directory.

The presence of LCK files indicates that a user has not exited the BDE
properly ( eg crash ), as the LCK are removed by the BDE when there are no
users accessing tables in a given directory.

It is possible, and I have done many times after crashes on our system, to
delete any and all LCK and NET files. Just make sure that NO ONE is using
Paradox tables at the time. The files will be recreated as needed.

Check points:
1. Does the IDAPI32.CFG that resides on the users machines all have the same
physical network directory ( use BDEConfig utility)? If not you will get
messages about multiple net files in use.
2. Do the LCK files seem to grow large? Then periodically delete them. I
regularly go on a scavenger hunt and remove all LCK files I find.

Sanity check:
If you are develping apps under the same environment as your users you are
looking for trouble. I develop on a mirror image of my users environment
(ie same drive letter and directory structure, different physical
locations). I then will transfer/update tables from my environment to the
user environment. I sometimes ( blush ) also transfer the LCK files by
accident and guess what? The BDE complains. Make sure that LCK files from
different environments do not mix.

Hope this helps
Jim

надо попробовать написать свою книгу...