Ravi,

Your build form had an instance of a class of the classlib in memory, this prevents VFP from being able to open that classlib in order to put it into the EXE you are trying to build.

When you say "standard class" do you mean one of the VFP baseclass objects?

>I check the form that has a button whose click event does the executable. On that form, there was a label from MyBaseClasses. I replaced that with a Standard class and did not get any compile errors.
>
>Why is that the Standard class worked? Some of my old forms still use the standard class buttons etc.