If you renamed the table BB-Code, VaultWiki doesn't know what its version of the code is anymore and can't handle it correctly. This is the BB-Code equivalent of varnames that you modified. The VaultWiki BB-Codes in the regular BB-Code manager are only placeholders (mainly for button icons, and Wiki Code Manager settings) and actually don't affect how the BB-Code is used internally. If you don't want to use VaultWiki's table code, disable it using the Wiki Code Manager.
There is no way to use both. In order to get it back now, you'll need to manually edit the database table bbcode and change the "tbl" entries to "table" that way. By the way, the syntax for tables are different between vBulletin and VaultWiki. If you want [tr][td], use vBulletin's instead. If you were using the VaultWiki table since before 4.1.4, you should continue using that.
Also, when you paste from Word, there is hidden garbage code mixed in with the table. Make sure to use vBulletin's Paste from Word button to insert your table this way. This will clean up the code and prevent weird things from happening every time you save.