Not sure why the pad would read the card but not play the samples, and I should mention here that the pad is kinda picky about the type/size card you use. I haven't troubleshot the right specs, but I know that some cards work, and some don't. But, if the card wasn't working, you wouldn't even see the sample names or be able to go through the loading process.
So, I don't know why your samples won't play, I haven't experienced that. If they're 16bit mono .wav files at resolutions like 44.1, 22,050, 11,025hz etc, and the pad sees them, it should play them. Does your pad play its internal sounds?
Bermuda