Table lookup cause "illegal operation" errors

[RASDAVIN]

Environment: VFP 5.0 app running on a Windows NT 4 server from a Windows 98 desktop.

I have a form set up which contains 4 lookup fields. One of the lookup fields occasionally causes an illegal operation error on certain lookup table records. Once the error occurs on a particular lookup record, it is consistent for a period of time and then somehow it seems to clear itself (for that record). The name of the lookup tablel is MODEL. The name of the field for the lookup is MODEL_NO and the name of the key field for the MODEL table is CODE.

Has anyone come across something similar to this? :-( Any leads would be appreciated.

 

[rgbean]

I have found that Illegal Ops like this are almost always due to a bad index on the lookup table. How it's getting "cleaned up" though is a msytery unless someone (or the app) is rebuilding/recreating the index file.

I suppose if the server (or the workstation) that is caching the index file has an occassional memory problem, then this could explain why a re-read of the file might "fix" the index.

Rick

 

[rgbean]

I have found that Illegal Ops like this are almost always due to a bad index on the lookup table. How it's getting "cleaned up" though is a msytery unless someone (or the app) is rebuilding/recreating the index file.

I suppose if the server (or the workstation) that is caching the index file has an occassional memory problem, then this could explain why a re-read of the file might "fix" the index.

Rick

 

[RASDAVIN]

Is there a VFP 5 patch for this?
Would upgrading to VFP 6 or higher correct this issue?

It puzzles me as to why only 1 of the 4 tables are affected, because they are all handled in the same way.

With regards to the index, is it possible that just reindexing would not completely clear the problem? Should I be deleting the index (CDX) file and recreating it?

Also, I am not familiar enough with Windows NT server and I noticed that some files stay opened on the server even when the user quits the app. Is this normal, or could this be contributing to the problem?