Error code -128

I am trying to make a script that checks to see if the programs I want to be running are or not, and then opens them if they aren't. I then want it to check to see if they are running, and then close them. I plan on putting this on a Quicksilver hotkey, and then having the script run it's functions.

I've got the script working to the point where it opens the applications if they are closed, but when I get to the quitting part, it gives me:

error "LCDManager got an error: User canceled." number -128

I am not sure what I can to do to stop the computer from auto cancelling this?

Here is my script code:

set appName to "LCDManager"
set appNameB to "G-Series Key Profiler"
set quitIt to false
set startIt to false
tell application "System Events"
 if not (exists process appName) then
 set startIt to true
 else if (exists process appName) then
 set quitIt to true
 end if
end tell
if startIt then
 tell application appName to activate
end if
if quitIt then
 tell application appNameB to quit
 tell application appName to quit
end if

Message was edited by: David Aaron