For a long while i hadn't been able to record in soundtrack pro, whenever i hit the record button i got the error

An Unexpected Problem
Uncaught exception


or sometimes it would say something about not being able to write an .aiff,

anyhow this is easily fixable by going into apples Audio MIDI setup and making sure the audio input is set to 16bit and not 20bit

now it works as it should, hope this helps someone else