I had the same problem, I uninstalled ads and now anywhere the wall exists (I have the IDBW wall, if that makes a difference, although ads are set to "off" in the wall config), I get a non-formatted page w/ the error msg "Table 'database.bx_ads_main' doesn't exist" on it.

The reinstall-ads fix works... but I want Ads uninstalled! Is that possible or is the ads module a required element? If I can't uninstall it, then is there a way to remove it from everywhere? I can get it see more off of the main nav menu, but it remains in the member menu profile links and on the site stats, so I can't seem to disable it from the admin menu.