Some times Google is >not< your friend. Most of the info found there relates to issues from July of last year.
However, a detailed search on this forum finds one more recent post that suggests the "current recommended" congif for FCP 4.5 is OSX 10.3.8 and QT 6.5.2. Is that the concensus opinion? If that's so, I may not be in bad shape.
thanks again -