I recently had problem with Adobe Digital Editions not downloading files from the MyMediaMall library website. It had worked initially, but developed a fault probably to do with Safari. I could download limited titles from the Adobe sample book web page but nothing from the library's site. To fix the problem it was necessary to remove Digital Editions from my computer and reinstall it. To remove digital Editions completely it is necessary to do the following.
To completely delete Adobe Digital Editions from an iMac with Snow Leopard OS 10 locate delete the following folders and files:
1. Under, /Documents/Digital Editions, drag the Digital Editions folder to the trash
2. Locate, /Library/Preferences/Macromedia/Flash Player/www.macromedia.com/bin/digitaleditions. Drag the digitaleditions1x5 folder to the Trash. Empty the Trash.
3. Open the "Keychain" utility located in Applications/Utilities. In the left hand column under category click Passwords. Locate and click "Digital Editions" in the main window. Right click this file and click delete.
4. With these files and folders deleted download and reinstall the Adobe Digital Editions software. It will be necessary to go through the authorization process again.
I hope this will save another Mac/Safari user some trouble in the future.