I'm losing MTS files when editing in Adobe

As many of you may know, or not, Adobe CS4 offers the AVCHD format. All one has to do is pull it straight into Premiere w/o having to convert the footage... etc. But at times it seems as though after I import the footage into Premiere some of the clips freeze at certain points. Mind you, they do not when I play them back on my Panasonic AG-HMC150. Then the entire program freezes. I have to wait for about 1 minute before it unfreezes. But the clips still freeze at the exact same frames. Premiere reports no warning - no nothing about any dropped frames or lost frames. So they should be there. Anyway sometimes when they freeze in Premiere a green frame pops up. I mean what the hell does that mean? I try doing a pre-render... it plays back fine but with frames missing and replaced by the green frame. So I tried rendering it out as an MPEG2 file. Samething happens. But at other times it works when I render it out and all the frames will be there... It's very strange.