Kinda crazy and tired right now, but if you want, post back and I'll give you the workflow for outputting for DCP. I've done a few of them. However, since your material is 1080 to begin with, if your venue will accept it, you might do just as well with HDCam or blu-ray and save yourself quite a bit of money with out much if any visible quality loss.
A couple of questions. Did you edit your h264 footage directly into the timeline? H264 is not fcp friendly and can cause all sorts of problems.
I strongly advise that you scale all footage whose pixel dimensions do not match your timeline settings before you edit them into the timeline. Compressor does a much better job of scaling than fcp if you set the resize filter to best in the frame controls tab.