As of my writing this, the current kernel is 2.6.26 (no suffix). That's exactly a 1/2 year newer, so I would try that first as it would probably help you in a lot of other areas as well. Note that the "git" is up to 11, so I'm sure a patch is right around the corner.
Beyond that, since I don't know what that board is, perhaps contacting the authors of the driver(s) for it may help. Worst case scenario is that you have flaky hardware either on the USB port side (but you didn't mention anything else) or that card--remember some cards are just POS's to begin with and no amount of software will help them.