The only VaultWiki version that is compatible with vBulletin 4.2.2 right now is VaultWiki 4 Beta 6. If you attempt to use VaultWiki 3.0.20, there will be compatibility messages at the top of site pages and the wiki editor will be distorted and difficult to submit. By the way, 3.0.14 which you are currently running has numerous security exploits which it sounds like you missed the patches for.
I would upgrade VaultWiki to 3.0.20, then wait on upgrading vBulletin to 4.2.2 until the VaultWiki 4 package conflict is fixed in Beta 7. Then you can install Beta 7, transfer your VaultWiki 3 data to the Beta, disable VaultWiki 3, and finally upgrade vBulletin.