Currently Being ModeratedDec 18, 2012 4:04 AM (in response to Jeeves123)
What happens, when you try to play the movies? Do you get an error message "Unsupported format"? Or do you only see a white screen? Are there any error messages at all?
What is the format of your videos? How have they been recorded?
Currently Being ModeratedDec 18, 2012 5:59 AM (in response to Jeeves123)
.mov can mean a variety of video formats - Qicktime is just a wrapper than can be used with several codecs. Have a look at the list of video formats supported by Aperture.
Can QuickTime open the video you exported from iMovie?
Aperture cannot show videos, when the when the com.apple.xpchelper.cache helper file is missing from the /System/Library/Cache, see this post:
If this file is missing, you need to restore it from your backup, or reinstall Lion; or use this mirror site, if you trust private copies: Re: Import video to Aperture library on Mountain Lion
Also you might check your video installed drivers, if you have incompatible video drivers installed: Aperture 3: May be unresponsive or have slower performance with third-party video codec