Will these chargers fry my Sansa Clip+?

I have two USB adaptors - one that has a sticker that reads Output: 5V ± 0.5v DC 400 ma = This one doesnt charge the Clip+ player. The other one I have has a sticker that reads Output: 5V 1000ma = This one charges the Clip+ fine. Not sure if the first one has too much of a lower current, or if its the voltage deviation of ±0.5v.