404 from breadcrumbs

I have a client that has had this issue since installing vbSeo. The breadcrumb that returns you to the main forum generates a strange link (http://www.site.com/forum/a/) and that same link is the one that all main forum breadcrumbs have. Any ideas what may be causing this or how to get rid of it?
Thank you.

Please try re-importing the product file with over-write.

I just did a re-import and upgraded as well, but the issue still persists. If I disable vbseo, it works OK.

Please make sure it works correct on default vBulletin style. This is related to your navbar customizations.

I reverted the navbar on the style and everything works correctly now. Thanks for the help!

You're welcome