After installing D4 C/S Update Pack 2, access violation error

After installing D4 C/S Update Pack 2, I tried to run exe (which ran fine
before).

When I clicked on the preview button, I got
" access violation error at address 00000000. Read of address 00000000 ".
When I tried to close the preview, I got
" control '' has no parent window "

If I deleted the preview command in the source code, it worked fine.

What happenend?
I read in the FAQ of QR, it has something to do with TApplication.Handle.

Can anyone explain to me what I have to do?