iMovie Keeps Saying: Sharing requires more memory to be available, Quit iMovie and relaunch it. I Just Bought My Mac And It Has Tremendous Amount Of Space Already, PLEASE PLEASE HELP

I Have So much extra space on my new macbook pro, Ive had i for about 4 months and Have taken very good care of it. I use imovie somewhat offten, but don't have all that many events or anything even, but imovie keeps displaying the message: iMovie Keeps Saying: Sharing requires more memory to be available, Quit iMovie and relaunch it. I have even deleted other videos and Have tried many other things, including resarting, re-opening (Rebouting) and Still get the same message. Plus iMovie is barley working since the message has begun to display. It keeps freezing and shutimg down on its own. I HAVE A VERY IMPORTANT PROJECT THAT I JUST FINISHED EDITING SO I CANT LOOSE THAT, SO I CAN'T DELEE IMOVIE THEN RE-INSTALL. Please somewhat help fast, cause the video project is due next week.

Thank You All Very Much!!

Zave