Symptoms:
While importing video from a hand held device, mostly mpeg4, Premiere pro doesn’t understand the format.
Solution:
Premier doesn’t edit mpeg files because the format isn’t as suitable for direct editing compared to a frame by frame format, like DV. For best results, one should convert the source video’s to such format.
It can be easily done with River Past Video Cleaner, a very versatile program. Look at this tutorial.