LUA Buglight™ is a tool to help both developers and IT Pros (sysadmins) identify the specific causes of admin-permissions issues (a.k.a., “LUA bugs”) in desktop applications running on Windows XP, Windows Server 2003, or Windows Vista. Once the specific causes have been identified, the bugs can more easily be resolved by fixing the app’s source code, or by making configuration changes, allowing the app to work correctly for non-admin users.
Aaron Margosis, the LUA Buglight creator, has plenty of good information on LUA bugs, including these articles posted to his blog:
What is a "LUA Bug"? (And what isn't a LUA Bug?)
Not every "access denied" indicates a LUA bug!
Fixing "LUA bugs", Part I
A systematic approach for working around LUA bugs that avoids unnecessary exposure
Changing Access Control on Folders vs. Files
More info on the risks of changing access control lists to fix LUA bugs.