Unknown Internal Error - BDE


we have an application with DBASE 4 tables under Delphi 2. Sometimes we get
a BDE-error : 'Unknown internal system error'. After that, one of the used
index files is deleted. (That means it doesn't show for the MS-DOS command

1. What may have caused that error?
2. Why is the current index file deleted ?
3. How can I protect my index files from beeing deleted after that error ?

Thanks in advance for any help


R. M?rte