I believe there is a limit...sounds like 30!  is there a reason why you have so many ad units?  not criticizing...just curious.  I know that with the insane head code (aka 2 part tag)...and some of the templated styles...there is no choice, but you may want to look into using custom criteria to identify different pages rather than using unique ad units.  Wish I had a better answer...but with the 2 part tags, this is just kind of the way it is.  :-(