Need some help with uploading content (MAC)

Ive been trying to upload some streams that I captured with Quicktime Pro (I am a Mac user). When I trying to upload the .mov files to Youtube, it told me that the files cannot be converted and therefore failed. I then tried to convert them to mp4 format and it worked. However, it gave me another error: movie too long. Now my question is how can I break it up into two parts? I wanted to import them to iMovie, but for some reason it cannot be selected for import...

Many thanks...

Did you use the File -> Import... menu selection?

I know that it won't let you drag&drop to open that type of file.

Maybe you just have to convert it back to .mov and split it using QT.