Racial Spellcasting and Prestige Classes

[Von Krieger]

My DM and I are having a bit of a clash regarding a character who has spellcasting provided by his race, and prestige classes.

Most PRC's say "+1 level of existing arcane spellcasting class," and though he agrees with me that my character has Sorcerer casting, casts from the Sorcerer list, knows spells as a Sorcerer etc, etc, that a prestige class that says "+1 level of existing arcane spellcasting class" cannot advance that casting, since I don't actually have any class levels in Sorcerer.

So I qualify for the class from my casting, by being able to cast the spells of the proper level. And yet he says the PrC cannot advance my Sorcerer casting since it's a racial and not a class ability.

I think this is weird, and that a source doesn't care if you have the ability from an item, a class, or your race, if you have the thing and the thing can be advanced, you advance it. :P

[Chronos]

For what it's worth, Sorcerer itself would advance your casting:
A spellcasting class is an associated class for a creature that already has the ability to cast spells as a character of the class in question, since the monster’s levels in the spellcasting class stack with its innate spellcasting ability. (http://www.d20srd.org/srd/improvingMonsters.htm)

[Divide by Zero]

For what it's worth, Sorcerer itself would advance your casting:

So worst case, just take a level of Sorcerer first and you're good to go.