Martin: No, your change deals with Unicode/SBCS/MBCS issues. Steven is complaining about the need for Global (as well as integrety level most likely).
You clearly understand the Global thing, but I didn't know about the Integrity stuff until just now. (It was added in Vista.)
See http://msdn.microsoft.com/en-us/library/bb250462.aspx#upm_ovwim for more information.
Steven's user process is most likely running at the Medium integrity level, his service is most likely running at the High integrity level.
This is also discussed briefly at http://stackoverflow.com/questions/113951/ipc-on-vista-service-and-application
The excercise the StackOverflow question addresses appears to be: http://msdn.microsoft.com/en-us/windows7trainingcourse_win7session0isolation_topic4#_Toc243675537
The excercise revolves around allowing the service and user application (system tray app, whatever...) to log to the same file.
The same rationale applies to the Event object you're trying to create here.
Yuck. I hope this helps.