To fix the problem, search and delete ALL:

PdoxUsrs.Net & pdoxusrs.lck

PdoxUsrs.Net is a system file created by BDE on the fly.
So, you can delete it.
Pdoxusrs.lck exists only if program crashed halfway, the files are deleted automatically when program exit.

For long term wise, you can try to point the Paradox.NetDir to c:\program files\edotwin
You can set it in BDEAdmin \ Configuration \ Drivers \ Native \ Paradox