Have you tried re-downloading it? I don't know what that would change, but try it...
Did that used 2.5, 2.6, and 2.7 various beta's, rolled back vista ran it in compatibility mode yada yada yada yada. I am really confused because less than 24 hours ago it worked and now its broke.
Post your question to the author of Real Temp, Kevin Glynn (unclewebb) at Xtreme Systems - http://www.xtremesystems.org/forums/showthread.php?p=3259472#post3259472