hmm, it's hard to say really.

There are two scenarios:

1 - the first line that came up was in fact a positive, but it was a negative on the second test because the urine wasn't as concentrated or as much as the first.

2 - the first line that came up was an evap and the second test gave an accurate negative result.

I'd suggest she try again first thing tomorrow morning.

It is still very possible to get a "false" negative at 10-12dpo.