Posted on uo.com's FYI

Ultima Online 9th Anniversary Entitlement Issues Nov 2 2006 5:12AM GMT (PST +08:00)
An intermittent issue with the entitlement process has been discovered that sometimes causes the application of the code to fail. Until the issue can be fixed permanently, the code can be applied successfully using the following steps:

1. Log into the Account Management website
2. Click the Upgrade Account link
3. Enter the code
4. Select the code you typed in and copy it (Yes, you will need this. Please be sure the code is entered correctly!)
5. Click "Okay"
6. Click "Accept" (click it multiple times if required)
7. When it brings up the billing info page click "CANCEL"
8. Click "CANCEL" again
9. Repeat steps 1 & 2
10. Enter your code again or if you copied it "ctrl + v"
11. Click "OKAY"
12. That’s it!