I suggest you do two things:
a. Wait for a few weeks to see if the stays post to your account. They probably will. If the stays don't post, then...
b. Call the hotel and have them send you a copy of the bill. Tell them that your *#$! assistant forgot to cancel the reservation and you need a 'normal' (not no show) invoice so that you can reimbursed from your employer. Alternatively, you could tell them that you are the *#$! assistant and that it is your butt if you can't get a normal invoice. If you plan future stays at the property, that would be helpful.
After you get the 'normal' invoice, use that to credit for the stay by submitting it to Hilton.
[This message has been edited by BillMorrow (edited 08-13-2001).]