iMovie "the movie file (filename) cannot be found" dialogue but WORSE! SOS!

Hi everyone.

Love iMovie. Have been using '09 for ages making great videos.

Today I decided to buy myself the upgrade to '11 for Christmas.

Here's the back story.

When i bought my mac I was running Leopard and iMovie '09. I worked with some footage then stupidly deleted the video itself, not from within iMovie. Of course i recieved "The movie file (filename) cannot be found. Without this file the movie cannot play properly" for each of the missing videos, every time I started up. This equated to 7 clicks on the cancel button before I got into the program. I just put up with it.

I then updated to Lion. Same problem no change, as expected I guess.

TODAY I download and install iMovie '11... and I guess because it's trying to gather all my previosu projects and files, it's now getting STUCK on that very first "The movie file (filename) cannot be found. Without this file the movie cannot play properly". The dialogue box actually reads "Generating Thumbnails. Processing event". Frozen. Stuck.

In sum

- I have two iMovie icons in launchpad, both open what i presume is the new iMovie because they act identically

- I don't want to lose all the previous work I've done.

- I've tried other help threads that suggest deleting the com.apple. blah blah plist files. No help.

---- I WANT MY IMOVIE BACK! I've got nothing now 😟

Any help I'm sure would not go unnoticed by santa!

SOS!