What could be causing this?

[Mellymonster]

On my test board it is fine, nothing at all wrong with this, but when I put it on my actual forum I get my forums out of line.

I disabled all my mods, and still its out of sink, whats up?

[Front Range 4x4]

The space between the categories is not "out of the box" vBulletin. You still have something modified so you may want to revert Forumhome and see if that taks care of it.

[Mellymonster]

That didn't work at all

[Lynne]

Since you have separated the categories into separate tables, there is nothing you can do to guarantee that the columns will line up. You can do your best by setting a width for the columns, but something can set the width off in one of the tables and it will no longer line up with the other tables.