Dear Don -
As something of an SBT Pro expert, this is very strange. I just tried it and had no trouble with this. The best test is to go into IC, to Inventory Receipts and try receiving something. You should be able to attach a Bin to the items received.

My only guess is that somehow you're trying to choose a Bin for things that are already in stock without a Bin. You have to bring items into the Bin first, then relieve them from that Bin (or Transfer them) afterwards.

Hope this helps. Glad I could give something back to this venerable forum. If anyone else has SBT questions, I'm on here a lot.

- John Kiernan