Just as the title states- whenever I try to move a live iguana from my inventory to a storage locker in the shed by the watertower near megaton (this shed is a mod), the game crashes. Is this a known bug?

Known MMM bug, I think. Pretty sure Mart fixed it for the next version. Just can't store live iguanas at the moment.

Of course it crashes. Putting an iguana inside a locker is cruel and unusual punishment. You could at least go to the Sniper Shack and put it inside Fluffy and Jitters' cage

Yea, known issue, patch already released, check out http://www.gamesas.com/index.php?/topic/1119869-relz-marts-mutant-mod-10-rc-61/page__view__findpost__p__16677278.