I had the occassional 'non-reading' problem when using a Mickey Mouse-brand CF card.
For Tossers-on-Tour I bought a 1Gb SanDisk CF card from eBay for £40.03p - delivered to my door.
1Gb easily absorbed enough for this tour and the SanDisk cartd worked faultlessly in my 2610 throughout.
Personally, I wouldn't buy any other brand.
Greg