lets say you summon 5 force 5 fire elementals, and command them all to aid you in learning a spell, now you have effectively 25 + sorcery dice to use in your sorcery test for learning the spell. If by the act of god you should fail, and decide to use a karma pool point to reroll, do you get all 30 somthing dice to roll again, or just the sorcery pool, or can you simply not use karma pool in this way?

You can't use elementals in that way. Only one elemental can aid you at a time.

Oh, and yes you can reroll the elementals dice if you use karma.

And allowing characters to use Karma Pool for such activities is an optional rule GMs may decide to use. See Extended Actions, SR3.246.

Example of GM applications of karma Pool: I allow the dice to be rolled if it came from a source that has karma. Dice from a aspirit could be rerolled. Dice from a medkit, or magloc passkey could not be. IMHO in thos circumstances you are putting your faith in technology alone.