I work in an Premiere CS4/Windows7 station, and have the same problem. Premiere generates peak files every time we open the projects, and name it VIDEOFILE 48000_1.pek and so on.
This occurs only when the media files are in an external disk connected via USB.
There is no display of waveform in the while.
I have tried to change the media cache folder and clean the cache database, without succes.
Hey people from Adobe, this is VERY ANNOYING. In old Premiere Pro 1.5 whith same setup and type of proyect this worked fine.