Problem viewing footage
Here are the Codecs for the footage:
XDCAM EX 720p24 (35 Mb/s VBR), Integer (Big Endian), Timecode
Original Format: MPEG HD
Well, there's the problem. You cannot EDIT XDCAM EX with FCP 5.1...for a few reasons.
1) a decoder would allow you to view the footage, but you couldn't RENDER it. You don't have that codec to render to...so it wouldn't work.
2) FCP 6 has the encoder for this, so rendering to that is easy. But it also has the ProRes codecs that allow you to render XDCAM EX to ProRes. FCP 5.1 lacks that codec, so you can't render to it. Nor does it have an option of another codec to render to. Why?
3) XDCAM EX came out AFTER...many years after...FCP 5.1 was introduced. Support for that camera is not in the code of the software...and when that camera came out, Apple did fix the CURRENT version of their software, FCP 6, to work with it. That was part of the .02 update...so you need FCP 6.0.2 at least to be able to work with that format.
The decoder is for others to be able to view the files...and maybe import them into their NLE or compositor and work with the footage...but then they need to export as another codec. Because FCP does things like wanting to render when you add an effect or transition, yet doesn't have a setting as to what to render to, Calibrated's doesn't support using their decoder with FCP. They don't have an encoder...only a decoder.
You can try...but I don't know what the ill effects will be. I'd advise against it...and suggest that if you must edit that format, you need to buy FCS2. But you will have to look for a used copy or a new copy on eBay or something...because Apple is selling FCS 3...and that version only works on Intels.