USB not mounting

I have a Verbatim SDHC 8gig card, which i have used to do some filming on a Panasonic GH1.

The card will mount on my old Mac (it's on Tiger), and on PC's, but WILL NOT mount in my Intel MacBook Pro (Leopard).

It shows up on new computer in disk utility, and when i plug it in, the light on the USB reader even blinks like its reading the card. It did actually mount ONCE on my computer, but that was once out of 20-30 times.

I have tried reformatting the card in Disk utility...

Is this a software conflict? HELP!!

If it mounted once, that proves the setup. If other devices work OK through your USB port, try a different USB cable with the SDHC card. If other devices are funky, then you probably have a bad USB port and need tech service.