David,
When I searched Stonefield libraries (simply using text search) I saw several places where he has lines "RELEASE CLASSLIB (tclasslib)". So I suspect that there might be something there. I am not sure it is a name conflict, the actual name of my classlib is "dlcalend.vcx" and didn't see anywhere in SF code this name.

I will let you know if/when I find out the cause of this problem. Knowing how things always fall on me <g>, I suspect I find out it is something I do wrong <g>.

>Dmitry,
>
>Unfortunately this app is still in VFP6 too, so your values should be fine. Be sure to post back the actual cause of what's causing your classlib to disappear out on you.
>
>I wonder if there is some code that is trying to "Push" the current classlibpath, install its own, then does a "pop" and it's not quite popping correctly.
>
>What happens if you move your classlib in the path? Does it still get eliminated? If so it's a name based problem. If it doesn't and another lib gets whacked it's a positional problem.
>
>>The len( set( "classlib" )) returns 1337 (and 1297 after "removing" my class library. Occurs returns 31 (and 30 after "removing" the classlib). I use VFP 6.0 btw, so maybe VFP 6 has lower limit.