If you encounter this error message when opening Adobe Photoshop CS2 in Windows XP, “The Adobe UI font could not be loaded” here’s a quick fix that worked for me. CS2 was doing this for months to me.
Search your system for a file called ADMUI3.fon. Copy this file into the Required folder in CS2. For example, “C:Program FilesAdobeAdobe Photoshop CS2Required folder”.
Restart Photoshop and there’s a good chance it’ll be fixed.