I have material from a canon HD camera, which uses the MXF wrapper format. Within each clip folder there is one CIF file, one XML file and a series of MXF files, each MXF comes with a SIF file. The movie is not in a format that QuickTime Player understands. How can I read them and import them into FCP 6?

MXF is not a format that QuickTime will read, you will need to convert the files to MOV format, it’s a compatible format. If you want to import into FCP, you can convert it to ProRes codec encoded mov format, it’s supported well by FCP and QuickTime. Pavtube MXF Converter for Mac is a program ever help me on converting my Canon HD camera video files well, hope it helps you also.
http://www.pavtube.com/mxf-converter-mac/