i have an error handler module, it works withe every single project, i want to make it one project for all sites a common place

sounds like you want to set a pointer to a folder outside the webroot of each of your sites. Open your Administrator, and go to Server Settings / Mappings and map something like /errorhandler/ to a folder up out of the webroot. Keep in mind that anything set by the application.cfc files inside your apps will not be in scope for those, so you will have to pass in things like auth info, dsns, etc. That being said, a global scripts thing sounds like a good idea, but be very careful. You're setting up a situation where a mistake in one file will not just take down a single site, it will take down all your sites. So be sure your code hygiene is up to scratch, practice code safety, test test test and have a DR plan.