have a look at this thread - maybe you have a similar problem.
When you did the Time Machine backup, did you install some software, or run some cleaning/helper/maintainance applications? This looks like a typical corruption of drivers needed to display/import movies caused by incompatible video software installation.
Is your profile signature still current (iMac (27-inch Late 2009), Mac OS X (10.7.4))? What is your Aperture version?
Thanks... for your try to help me... it seems that timemachine backup is the guilty... the right way to got the movies back in aperture is the following...
on Macosx LION
1 - reboot and maintain cmd - R
when the menu prompt you to choose what to do
2 - select install macosx LION
3 - enter your apple ID
(the F.......G language selector flag is on the upright at the screen i see it after on my 27" why do you have made so little? do you imagine how hard it is to tape password and name in qwerty when you got an azerty keyboard... shame on you)
4 - wait the job to be done
5 - your mac reboot and work
Now aperture seems to work correctly, i can see the movie on my canon EOS 7 and import them, all the old movies are back