Post up your Export settings.
From the export settings window:
Preset HDTV 1080p 29.97
Summary: NTSC, 1920x1080, 29.97fps, Progressive, AAC, 160kbps, 48khz stereo, VBR, 1pass Target 32, Max 40.mbps
My source is 1920x1080 (1.0), 59.94, Progressive
Why are you changing 1080p/60 into 1080p/30? That'll cause issues.
Also, what is the intended delivery here? Just computer playback, or something else?
As a new trial user/potential buyer of CS5.5, I have not yet discovered the means to get an output different from the available 1080p30. I realize now that I mis-typed earlier that I was trying to output 1080p60 when, indeed, I was attempting to do so with 1080p30 instead. Sorry about that.
At the moment, I am investigating the possibility of creating nature DVD's to sell that would be on DVD (BR if possible) and presently, I am looking to test market my product on Vimeo and Smugmug. So... short answer I guess: Higher quality PC playback now with potential HD disc marketing around the corner.
I read elsewhere that people suggest changing camera settings to going to 1080i or 720 settings instead of 1080p60 to avoid some of the pitfalls that I (and others apparently) seem to encounter with these files.