You don’t mention what your sequence settings are….
But, If your trying to playback off your internal drive – this could cause playback issues. Are you working in HD?
It doesn’t mean the clip is bad or anything.
What are your plans with the exported clip?
Are you next compression for DVD or web?
Put the exported clip on a fast drive or re-import back into FCP to have better performance.
Chris Tompkins
Video Atlanta