I would like to run 4 or 5 different sites, each with a unique domain name, and each with a radically different theme, do I have to have multiple versions of Coppermine installed, or can I even do it with the locking file coppermine creates for mySql?
To run different galleries on different domains, you need to have an installation for each domain since the gallery needs to have the correct gallery URL in Config for some functions. The lock file is specific to each installation so as long as you install them in separate folders, they won't affect each other.