Sorry from bringing this thread from the the dead. But I found a "workaround" for the Headers Form bug reported here and hence It might give you some clues for what's wrong.
First of all I am using a new clean ubuntu 6.10 with (almost) default settings and I just downloaded the svn 3222 revision in .deb file. And the problem still exists. BUT, If I go at the gnome menu->prefernce->fonts->details press advanced and change dpi from 96 (the default) to 72 (I think that's the window default) the new header form now is large enough. So I think it needs a check for DPI issues.