Nah, no need to be worried, I think. Do you have QuarkXPress 6 installed?

There seems to be a conflict between the note in

display dialog "The Launch Services rebuild is now complete." buttons {"OK"} default button 1 with icon note

(that note is from the "Standard Additions" scripting additions that are a part of a default AppleScript installation, specifying the particular icon to appear in a dialog)

and a botched syntax in the scripting additions installed with QuarkXPress 6.

If that's as plain as mud, this should make things even murkier.

(My guess is that the changed nature of what "the «script» doesn't understand" reflects changes in AppleScript since the date of the above link (3+ years ago), not any real difference in the underlying conflict.)