Ableton is using “aifc” (at least on Mac OSX anyway) under the hood, even though it shows as aif. You should be able to export as wav but this is only a solution for one or two samples - there are lots of conversion utils out there that will handle batch processing aifc to wav, the trick is finding one that works reliably - do some serious research before you buy any conversion software.
It would be interesting to know if this issue is just on Mac - so can Windows users get away with straight import of Live samples to OT? - I believe the aifc thing might be just an Apple wierdism…