I would not use this script for something you want timed by a button press.
The script is intended to call a common event at the moment you walk onto a tile with that region id. Chances of you timing your button press to exactly the moment that triggers are incredibly slim. And as Andar mentioned, you would need it in a parallel process so it keeps on checking just in case it missed it the first time.
In short - don't use this script. Have a parallel process event on the map that turns on a new switch then erases itself. Set your common event to parallel process and condition it by that switch. Do the test for the button press, and then use Get Location Info to get the player's region into a variable. Finally, test whether that region is any of the ones you want to know about.
If you need further help, please start a new thread in the Support forum, as it will no longer be an issue/question about this script.
Also, Erase Event does not work on common events. Only on map events.