Scrolling text in FCP 6

I am using FCP 6.0.6 with iMac running 10.6.8. I am using Boris for scrolling text but I am getting double/"ghost" credits when they scroll upwards. My credits are simple - just lines, no graphics and running a maximum of around 30 seconds for about 20 lines. I don't know why there is ghosting on them. 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 getting ghosting on both outputs. Any advice welcomed! Thanks.