I have seen this problem on Tom's before. No one has found a solution to my knowledge.
Do other USB hook-ups work? Or do you have any other USB devices to try?
Also, what format is it? FAT32? Try converting it to another format (only if nothing else works).
Also, support line is 1-800-425-0049 for Staples. Give that a go if you don't find any info online.
Thanks for your feedback!
I was able to correct the problem by using my Dell support and download the driver from them.