Hmm, not good, sorry about that.
That would have been one tested by the assembly house. So either they missed it somehow, or it is somehow intermittent.
First check from the negative output to either side of the battery, you should measure +/- half the battery voltage.
As for the batt light, there isn't much that can go wrong there, U3 shouldn't be faulty I wouldn't think. There has been the occasional report form the assembler of failed switches, so perhaps that could have something to do with it?
If you email me your snail mail address I can ship another one.