[Chris Trim]

OK, there are two issues here – importing MP4 footage and then working with it.
First things first… MP4 is a compressed format unlike DV. This makes it a pain to edit and Premiere Pro starts choking on it when you try to do for example a multi-camera edit with different file types.
Anyway, here’s how to import MP4 into your project:
1. Click “File” > “Open in Bridge…”
2. Browse to your MP4 media and double click on it. It will now appear in your project asset panel.
3. (Optional, but recommended…) Create a new sequence with 1 video and 1 audio track and drag your MP4 asset onto the timeline.
4. Click “File” > “Export…” > “Media” and it will launch a new window for you to enter your export settings. I suggest something like the following in the Export Settings:
Format: Microsoft AVI
Preset: PAL DV (for UK or NTSC for US – if your footage is widescreen select that too).
Location: Preferably a different hard drive to the one where your source footage resides but in any event choose one with a high read/write speed.
5. Go to bed/pub/school etc while Premiere transcodes the media for you! It takes forever! You can queue a number of files for transcoding and save your output settings as a preset. The resulting AVI files will be considerably bigger than your MP4s, so make sure you have enough space! I’ve just transcoded a 3.8GB MP4 and it is now a 8.6GB AVI file!
6. Delete the timelines from your project with the MP4 assets and just work with the AVIs. Premiere will love you again and you will be able to apply effects etc to your heart’s content.
My other advice is to sell your camcorder and buy a secondhand DV tape camera. That’s what I’m about to do!