Having latency problems when track is playing...

[9:45]

Yeah its weird for some reason when i try to input midi on to a channel when i am re sampling or either just playing back a clip i get huge cracks in the audio but when i just hit the record/arm button and stop the track i can play midi fine without any distortion or anything! does anyone know why this is happening i cant find an answer online and i know why way around a PC very good, but i just can't figure this one out any suggestions from anyone? I would appreciate any feed back thank you, Nine

[crumhorn]

Probably not relevant to you but.. is the disk drive on the same fire wire interface as the sound card?

I had similar problem in the past and that was the cause.