Pell-Mell said:The ability to use spell-like abilities to satisfy prestige class prerequisites is found in the Complete Arcane (page 72, under "Specific Spell Requirements").
Slaved said:Where does it say Spell-Like Abilities are Cast?
A requirement based on a specific spell measures whether the character or creature in question is capable of producing the necessary effect, and as such, invocations and spell-like abilities that generate the relevant effect meet the requirements for specific spell knowledge. For example, a prestige class with a spellcasting requirement of "Must know (or be able to cast) darkness" is met by a warlock who chooses darkness as one of her invocations, or any creature with darkness as a spell-like ability.
Complete Arcane said:A Warlock cannot qualify for a prestige class with spellcasting level requirements, as he never actually learns to cast spells. However, Prestige Classes with Caster Level requirements, such as Acolyte of the Skin, are well suited to the Warlock.
Complete Arcane page 72 said:Characters or creatures that use Spell-Like abilities or Invocations never learn the arcane circumlocutions of logic and mental training necessary for advanced spellcasting. As such, requirements for Feats and Prestige Classes based on specific levels of Spells Cast ("Able to cast 3rd level Arcane Spells," for example) cannot be met by Spell-Like abilities or invocations that allow a character to use a specific Arcane Spell of the appropriate level or higher.
Slaved said:I do not think that means what you are saying.
For another reference I did found on Page 18 in Complete Arcane a reference for the Warlock.
Earlier on the same page you referenced your quote from I found another piece.
These sections including the one you referenced are talking about Feats and Prestige Class requirements so it is not certain that they apply to Spell Effects at all.
What we do know is that Spell-Like Abilities are not actually spells and they are not actually Cast. The spell Ogrork the Mighty asked about detects Evil creatures with the ability to Cast Divine Spells.
If the spell in the original post looked for a specific Divine Spell might be different based on your reference but since it looks for a general ability I think that the references I put here are a closer match.