Ok - in my quick look thru things, I couldn't find an answer. So I'm throwing it out here for help.
In qualifying for a PrC, do ability modifiers count as ranks in skills for PrC prerequisites?
No. The only thing that counts as a rank in a skill is a rank in that skill, the kind purchased with skill points. Additional modifiers, such as those granted by ability scores, feats, magic items, and the like, are not ranks.
ok, that's what I was thinking. I have a PC who has relied on "natural talent" over "training" and now cannot qualify for a particular prestige class. Sux to be him!
(I usually DM, so some character-creation nuances are...rusty)