Need more input
Please specify in which program you are trying to import your material?
iLife'08 is very picky on the format of video footage you import.
Final Cut Pro will accept practically any video type .... but ... beware that certain video formats are not really practical for editing in FCP.
In your post you use MOV and MP4.
1) MOV is not discriminative. MOV is only the "container". In the container you may encounter audio, video, stills or any combination. Inside the container the CODEC will define the real format of the data.
Test: open your MOV file with QuickTime. Go to Window > Show Movie Inspector. The popup will show the details of the "real" format (expert level: real is set between quote as QT does not alway tell the truth - Ref properties in DVDSP)
2) MP4 is a very powerful DISTRIBUTION format. It is small in size, uses very high compression and requires a decent CPU to decipher the content. Ideally for distribution on the WEB. NOT SUITABLE for editing, though possible in FCP.
Editing in MP4 is doing (de)compression all the time, and each time loosing data due to the compression. When having no choice, be very patient as it will be very demanding for your CPU.
Good luck.
Coen