I just downloaded the trial of the prospect 4K. After converting my footage with filmscan2 to Cineform AVIs, I just imported them to premiere. Whenever I was trying to cut a video into single frames (sounds crazy huh?) and manually duplicating the frames I come across this playback issue. The indicator goes back somewhere in the timeline and stops.
It also happens in effect applied and rendered footages.

Windows XP Pro
Adobe Premiere Pro CS3
4GB RAM
Intel Q9300@2.50 GHZ
NVIDIA Quadro FX 1700
Non-RAID multiple HDDs

Use Ctrl+space bar to play through those single frame sequences. The playback engine will struggle with so many frame seeks. When Premiere preview renders, it so produces one frame clips. The Ctrl+space, will play use the default Premiere engine will play as fast as it can, while not as fast, it should manage those complex bits.