Does she actually have an e-ticket number, not a PNR, but an e-ticket number. Tickets can take a while to issue and if she doesn't have a ticket, she won't be able to check in (or fly).

What did VS say when she (not you) called to ask why she can't check in?

This could be related to:
1. Simple need to verify docs.
2. Standard problems with tickets issued at the last minute, e.g., ticket no issued.
3. Fraud concerns.

So, she really needs to call sooner rather than later.