G9 Movie stutters

I mainly bought the G9 to have a compact MPEG Movie camera in my bag all the time.

I used to have the S80 and used the video a lot, its great. But I swapped the Standard 2Gb SD card from the S80 which used to work faultlessly and I have about 50% video glitches. Sent it back to Canon twice but still there is glitching. I've ordered a new SDHC Ultra II Card, hoping that it may be a better compatibility with the G9. No one I know seems to think the Memory Card could really be a problem but does anyone else have any idea?

Cheers,

Sam (Sydney, Australia)