Just updated to Xcode 5 and this is the first error its throwing on the logger for all my apps. Can\'t seem to understand why this is happening.
2013-09-
After reading Kirill's answer I did some digging as I didn't want to disable BetterTouchTool for everything just the "iOS Simulator" and you can. Open the "iOS Simulator" and will it as the active app go to the BTT drop-down menu from the top bar (of that screen if you have more than one) and select "Disable BTT for Current App". It will turn to a play icon when it's disabled. Make sure the app name on the bar is still "iOS Simulator" as mine jumped to "Finder" a few times when I clicked the top bar!

Now re-set the simulator (if it doesn't work) and rebuild. You shouldn't get the error! :) Don't forget to clear the error if it's still there. ;)
BTT seems to remember what apps it's disabled for (or at least it does when you close and re-open the app that's disabled I haven't tried a system re-boot yet).