Blog categories

Hello,

I've recently used the multi-db plugin.
It works just fine, thanks a lot.
I still have an issue though ...

I was using a plugin to categorize my blogs ...
But now it doesn't work anymore, and I don't understand why ... I still have a table wp_blogs_certi_categories in my wpmu_global ... But nothing works from a blog perspective, neither at the home page or elsewhere ...

How could I solve this annoying issue ...