Thank you for your help. Somehow or other everything spontaneously started to work again. I did quit iMovie but I did not have to shut down my computer. You are correct about the fact that I had just uploaded a bunch of new stuff because I had downloaded the Maverick system. Then I had to upgrade bunches of iWork stuff. That is when the problem started. Next time I will just quit whatever and maybe even shut down to see if everything is resolved without all the detail in your thread. Nan in NJ
As long as everything is working fine, I would leave the files as they are; I would not advise permanent deletion of the files unless you have a backup (maybe through TimeMachine or even an external hard drive). Even as of now, 6 months after my initial response to the thread, these files are still in my Trash. I have not permanently deleted them...just moved them to the Trash. I haven't experienced any problems with iMovie since this solution.
I hope this helps.
Same issue. I cannot drag and drop clips from Events into Project. There does not appear to be a workaround. I note that this has been a problem since the date of the OP: 2011. It's now 2015. At this point it's safe to assume that we're dealing with an "undocumented feature". The program likely has an irresolvable issue. Since it's a freebie, I'm guessing that it's not much of a priority, and we're invited to pay for a more robust, 3rd party program.
Did you check out the response from TNethers on page 3 of this discussion? Those suggestions are what worked for me...also see my response on page 3 of the discussion, as I had to make a couple of minor tweaks from what was suggested by TNethers.
I hope the solution will work for you, as well. Good luck.