>>>Try:
>>>

>>>oMyVCXClassinMainEXE = NEWOBJECT([ClassName],[ClassVCX.VCX],full_path+[Main.EXE])
>>>

>>
>>Thank you Borislav,
>>but I think that this would not help.
>>
>>Infact, I create objects stored in classes compiled in the MAIN.EXE without problems.
>>
>>Is when I try to launch a form compiled in the CHILD.EXE that uses classes stored in the MAIN.EXE that I got the infamous "ERROR INSTANTIATING CLASS" error.
>>
>>Example:
>>The MAIN.EXE includes a MYTEXTBOX.VCX class.
>>The MYTEXTBOX.VCX class includes a class named TEXTBOX_EMAIL.
>>
>>I use this class in many cases and therefore in many forms.
>>
>>AT DESIGN TIME, in a form contained in the CHILD.EXE, I add a TEXTBOX_EMAIL control.
>>
>>The MYTEXTBOX.VCX in included in the MAIN.EXE and excluded in the CHILD.EXE
>>
>>This situation fires an error.
>>
>>Nicola
>
>Nicola,
>
>Don't know, but have you tried
>

>SET CLASSLIB TO MYTEXTBOX.VCX IN MAIN.EXE  ADDITIVE
>

HA!
This should works.
I am glad I learn something today :-)
Thank you.