The time has come...
...to update to Delicious Library 2.2. As of August 15th, 2009 (that's in four days!) Amazon is requiring all users of their data (us) to digitally 'sign' requests for information.
In English that means Delicious Library is no longer going to work unless you update to 2.2 (or 1.7 if you're still using Version 1.)
When you next launch Delicious Library (1 or 2) it should prompt you to update. Do it! If for some reason you need to download the update directly, you'll find them below.
Download Delicious Library 2.2: DeliciousLibrary2.zip
Release Notes for v2.2: Delicious Library Version 2.2
Download Delicious Library 1.7: http://www.delicious-monster.com/downloads/DeliciousLibrary.dmg
Release Notes for v1.7: Delicious Library - Release Notes
Good luck, and if you have any problems, let us know!