Hello Paula1040,
Thank you for using Apple Support Communities!
I was researching what might make iMovie quit unexpectedly on you, and found a great article to help troublehsooting that issue.
iMovie: How to troubleshoot "Application Unexpectedly Quit" messages
http://support.apple.com/kb/HT3143
2) Disable non-essential QuickTime components.
- Navigate to /Library/QuickTime/ for a list of components currently installed.
- Temporarily disable any components that are not in the list below. You can disable the components by moving them to the Desktop or another folder outside of the /Library/QuickTime/ folder.
- Open iMovie and see if the issue is resolved. If iMovie no longer unexpectedly quits, check to see if an updated component is available, or contact the developer of the component for further recommendations.
iMovie uses the following components, and should be left in the QuickTime folder:
- AppleIntermediateCodec.component
- AppleMPEG2Codec.component
Note: There may also be a similar folder at ~/Library/QuickTime/ depending on the components you have installed. If this folder is available on your Mac, remove any components as instructed in step 2. Both of these locations hold QuickTime components. The components help you encode or decode different types of multimedia content.
3) For iMovie 6 or earlier, try disabling iMovie components provided by manufacturers other than Apple. Start by quitting iMovie 6. Navigate to ~/Library/QuickTime/ and /Library/QuickTime/ and use steps 2 and 3, under "Disable non-essential QuickTime components," to determine what components to disable.
4) Check the Knowledge Base.
Search Apple's Knowledge Base for further recommendations. You can use search strings such as "iMovie unexpectedly quit" to locate new or updated articles describing specific iMovie scenarios and possible resolutions.
5) Run Apple Hardware Test and Disk Utility
If you are experiencing unexpected behavior in other applications, check your hardware by using Apple Hardware Test. You can also test your hard disks using the Verify and Repair functions of Disk Utility.
Note: If the issue only occurs when importing footage from a camera or device known to work with iMovie, consult the articles "iMovie '08: Cannot see or control camera" and "iMovie 6 or earlier: Cannot see or control camera" for additional recommendations.
Important: Information about products not manufactured by Apple is provided for information purposes only and does not constitute Apple’s recommendation or endorsement. Please contact the vendor for additional information.
Regards,
Sterling