Sue:
Here is another wrinkle on the problem you mentioned. I use the USPS Shipping Assistant and then apply my own postage stamps to the label. Remember I'm shipping to stamp collectors and they frown on the barcode postage. Anyway, I too have a customer in Latvia and it refuses to print the label. It's just a label no postage no USPS commnitment. When it happened the first time I asked the clerk about it. I was told that it had to do with Customs. The labels printed either through click and ship or shipping assistant have a customs barcode. So that may part of the reason for them not allowing you to print postage.

Garry