Open the product file 'product-vblinklist.xml' and have a look at the first lines. Change the version number of the line where you find the dependency for vBulletin:
PHP Code:
<dependency dependencytype="vbulletin" minversion="4.0.8" maxversion="4.2.0 Alpha 1" />
Instead of 4.0.8 choose another version, save the product file and try you best if it works. I dont guarantee that it works, but its worth a try.