Did you try copying and pasting them out. What kind of card is it by the way SD,XD ...? Is it locked maybe, I don't think it should affect it that way though if it is, but trying can't hurt. Also sometimes the cards memory gets sort of messed up and then you need to use something more professional to get stuff off of it. I had a similar problem with my SD card and i ended up reformatting it but I lost everything that was on it, none of it was really important anyhow though. I have a friend whose card was messed up so he brought it to a photo shop and somehow they got some of the pictures off of it. I don't know how they do it though. I suppose there is some program you can get that would do the same thing as they did.
In general because of problems like this I think the cards are supposed to be reformatted every so often (you lose your pictures when you reformat so make sure to copy everything off when you do it though). sorry i can't help more, hope you find a solution.
Zvi