scrolling text in fcp 6

I am using FCP 6.0.6 with iMac running 10.6.8. I am exporting my finished work using Compressor 3.0.5 using pre-sets for H.264 and Pro Res 422 for playback on Quicktime. I am using Boris for scrolling text but I am getting double/"ghost" credits when they scroll upwards on both outputs. My credits are simple - just lines, no graphics and running a maximum of around 30 seconds for about 20 lines. There is no ghosting when playing the FCP file so I assume it has something to do with the export maybe? Any advice welcomed! Thanks.

Mac Pro 2.66 mhz, 2GB RAM, 250GB HD, 500 GB HD, Mac OS X (10.6.8)