iMovie 11: issues generating thumbnails with large import

I have a HDV tape that was in a flood, and is not in great condition (It's a sentimental family movie). It imported OK, but iMovie recognized scenes really weird, in that it separated the 60 minute tape into so many segments (157) that it's causing fits for iMovie to generate thumbnails. At the import, it got all the way to the point where it said it had 1 minute left -- but it stayed there for over 3 hours. So I "forced quite" iMovie. I relaunched it, and it did basically the same thing -- it got to a minute left, then stayed there for several hours. So I forced quit it again. This time it got to the point where it said 4 hours left, and I left it over night. It was in the exact same spot this morning. So I forced quit, then rebooted the whole computer. When it came up this time, it said it had less than a minute, but it's now growing in time (the bar is moving towards the right, so maybe it's working...we'll see).

The problem is now, as soon as I boot up iMovie, it automatically goes into the generate thumbnails mode, and I can't do anything else with it. So, my question is 3 part.

1. Is there a way to get the import process done, so that I can start to edit the video.

2. If I can't, how can I clear this project, so that when I start iMovie, I can do something else with it?

3. I have 8 HDV tapes in similar condition (some worse than others) -- what is the best course of action to extracting all the movie that I can from the tapes?

Thanks