[Olli2k]

Ok, i've got it:

In Admin CP also activate:
Disable BB Code Within This BB Code: YES
Disable Smilies Within This BB Code: YES
Disable Word Wrapping Within This BB Code: YES

With the update to 4.0.3 vb converts the url for the flash param to the [.url][./url] tag. So that's why there is the "File not found" msg.

After setting up the BB code, edit your post and remove the url tag and everthing should work fine!