Corsair are lifetime warranty aren't they, and they do RMA if you can't run them at 1066 5-5-5-15.
Those sticks have EPP, Enhanced Performance Profiles, old version of XMP I am guessing, can you not enable EPP?It's good ram!
Might be in the ai overclock menu, have you tried the other fsb-nb strap settings Matt? Had a p5q deluxe, found that with 1066mhz ram, running 333mhz fsb-nb strap allowed the memory to run a bit higher than 800mhz, albeit that was with a q6600 and a q9550, (3.8ghz on each cpu) both needed a fair bit of tweaking of pll, nb and fsb-termination voltages
Why on earth are you overclocking your girlfriends pc, she'll get her shopping/browsing done faster, unless she enjoys the battlefield too??