I know that the problem was posted once before several months ago, but since there was no solution until now, just continue:
I use Premiere CS5 and imported videos can not play anymore. Thought at first that it has something to do so, perhaps, that I recently use a DSLR and anything with the format is wrong, but old videos (; PAL) work more synonymous again. The clips start and stop at irregular intervals easily.
If anyone has a solution, I thank schonmal for the answer!