If no one minds, I'll just step in and give my two cents, having thorough experience in both languages.

Armand, on Oct 14 2009, 04:08 PM, said:
@27 = ~I say "Nay". You're nothing but a pesky fly.~ // What is a pesky fly ? I've some difficulties to understand.
A pesky fly is an *annoying* fly. i don't have the context, but I'm surmising that this line is actually in reference to a person. You might want to try "satané bougre", or even try to adapt the entire sentence, such as "Tu n'es/Vous n'êtes rien de plus qu'un bourdonnement dans mes oreilles".
Armand, on Oct 14 2009, 04:08 PM, said:
@55 = ~Oempa loempa, dample dee dee.~ // What's the meaning ?
This is actually a reference to the 1971 film
Willy Wonka and the Chocolate Factory. It's a song the little oompa loompa's sing. Translating this one's going to be a though one. You could try a French children's song (mais j'ai pas top d'inspiration sur le moment).
Armand, on Oct 14 2009, 04:08 PM, said:
@119 = ~Why in the Nine hells are ye coutin' that way for ?~ "Coutin'" That's the same meaning that "cout in", no ?
It's a colloquial form of the verb "counting", probably to convey a dwarf or a rogue or some commoner's way of speaking. Tu peux essayer "Pourquoi, par l'Neuf Enfers, compte-tu com' ça ?". J'ai pas mieux.
Armand, on Oct 14 2009, 04:08 PM, said:
@126 = ~Oempa loempa dample dee da. Whith my own songs, I've killed my own ma.~ // The same problem for "oempa loempa dample dee da"
See above.
Armand, on Oct 14 2009, 04:08 PM, said:
@226 = ~And why do you this, cuckoo ? ~ // Cuckoo ? What is it ?
A cuckoo is a kind of bird (un coucou), and it's usually used to imply that someone is daft, crazy, out of his/her mind. How about "Et pourquoi fais-tu cela, espèce de maboul ?" ?
Try to avoid that light teal font, I can't see it with the asylum config.

Oh, and si t'as d'autres questions, hésite pas.