I got a PM from another member today that said this:

Jennifer - the 2 books i sent to you came back to me today as "undeliverable, unable to forward" and there was a marking on them that said "NSA" which the mail man told me means no such address. the addres they were sent to was the one on the PBS label -

I checked the address, and it's correct. If I remember correctly, I've gotten a couple of other books where the sender used the PBS label, and they were delivered fine. What do I do?

Contact your post office.  Make sure your address is in the database. 

(I had a landlord who added unit numbers without approval.  Was a nightmare until my local post office gave me advice on how to get it okayed.)

I've gotten other books from PBS with (and without) the PBS wrapper (and PBS DC), so it's really weird that the address would be marked NSA.

Yep.  Some of my mail arrived.  And some didn't.  Bills being returned?  Argh. 

Check address at:

http://zip4.usps.com/zip4/welcome.jsp

I went to my local PO today and the clerk was REALLY nice. She said that my street is on 2 different routes (it has 2 parts), and the mail must have gotten mis-sorted. We apparently have several new carriers, and she said that probably instead of throwing the package back in the bin to be re-sorted, they sent it back as NSA. She also said that the sender shouldn't have to pay any additional postage, just take it back to the PO and explain to them what happened. Yay for nice postal clerks!

eta: thanks for the advice!

Jennifer - when you send the PM to the original sender, also send  her a copy of the message above from when you talked to your postal people.  She may have a CP (cranky pants) postal clerk who won't accept what the original sender is telling her, when she tries to get the package back to you.  Pat