That appears to rule out networking issues completely which is very interesting. My experience so far has been that this error is typically caused by dropped network connections, interference, or poor connectivity. Fixing that has removed the error in all but two locations for me. Now your most recent experience points to something entirely different, but what exactly? It will be VERY nice to know if it can ever be narrowed down.



>>Were you still getting the error before you changed your ALLTRIM(UPPER()) indices?
>
>We haven't changed all of them in our main tables. I think I was still getting the error after I've changed stage tables indexes.
>
>I ran three tests yesterday for big loads. I then ran the original version of the program but didn't wait for its finishing. And today when I came in I saw the messagebox (I put a time spent in messagebox), but didn't see the result and it was gone. Then I tried another test with the original program and got the error right away.