>When I got this problem I was trying to add the object from within a button click method - my code was similar to yours & had the effect of trying to add the object to the button, rather than the parent form.
>
>Using the AddObject for the form cured the problem.
> e.g. MyForm.AddObject( "okcal", "thecal" )
I am trying to use this technique to create a MAPI session on VFP 5
I have a class file with the definition and using the form to access the MAPI
variables..

--- Class file ---

DEFINE CLASS MAILW AS FORM
windowtype = 1

add object oleSession1 as oleSession1 With ;
top =0, ;
left = -4,;
height = 180,;
width = 269,;
name = "oleSession1"


add object oleMessage1 as oleMessage1 With ;
top =0, ;
left = -4,;
height = 180,;
width = 269,;
name = "oleMessage1"

ENDDEFINE


DEFINE CLASS oleMessage1 as OLECONTROL
name = "oleMessage1"
oleclass="MAPI.MAPIMESSAGE.1"
oletyeallowed=1
enddefine

DEFINE CLASS oleSession1 as OLECONTROL
name = "oleSession1"
oleclass="MAPI.MAPISESSION.1"
oletyeallowed=1
enddefine
---
var = createobject("mailw")
and I use the Thisform.addobject("var","mailw")
but then It comes back with the following error:

OLE error code 0x800401f3. Invalid class string..
what Am I doing wrong??

thanksss

Mark