For his Audio/Video Settings in FCP, the Sequence Preset should be "DVCPRO HD - 720p24." In FCP 5, if that setting is something else, he'd need to render your footage to match the sequence. I believe that changed in FCP 6, so that you can edit different formats on the same timeline.
The easy fix is for him to start a new sequence with the proper preset.
[Sam Waldorf]" I mean just set it to DVCPRO 720p at 24p and it won't need to render initially right?"
Absolutely right. He just needs to just pull down the Final Cut Pro menu (right next to the "Apple" icon on the far left). Then he selects "Audio/Video Settings...," and in the next window he pulls down to the proper "Sequence Preset." In this case it would be "DVCPRO HD 720p24."
but, while I'm on the topic, I'd been told that in Final cut 5 you can't edit different resolutions and frame rates in the same timeline, based on what you just told me though, can you edit different ones if you either render or switch the setting back n' forth?
[Sam Waldorf]" can you edit different ones if you either render or switch the setting back n' forth?"
Yes and no. Once you establish your Sequence settings you can't change them. You'd need to start a new Sequence.
It is possible in FCP 5, just as your editor is now doing, to take different formats and slap them on one timeline, but not only do you suffer the time it takes to render, you actually change the format of what you shot to match the Sequence you just set up. So it really doesn't make any sense.
Best to just use the proper settings to begin with.