Run time error 398

Hello,

I have developed a database with a MDI form and some child forms, which hold the clients information. I'm using some controls that I have downloaded form vbaccelerator.com and I'm using some of them on my MDI form like the explorer bar, tool bar and some s2 grids. Each child form holds about 7 grids.
The program runs well under vb6. Yesterday, I decided to compile it and create a package with the visual studio tool.
When I install the package on my computer (windows xp home) everything works well but when I install it on windows xp pro or 2000 I get the error "Run time error 398 CLient site not available"
When the program install, everything is installed on the app folder. It looks like that the problem comes from the child forms because I tried not to allow the MDI form to load those forms and then recompile it and the MDI then will load fine but without the child form.
I really don't know what is the problem. Any suggestions?
Thank you for reading my message.
Chris