are the mice all the same brand?
some mouse drivers are set to do different things with extra buttons and scrollers. Some mice also have a utility program to change what the scrollers and extra buttons do when used.
Check these first and let us know if its still happening.
If the status bar is hidden and locked, scrolling through records using the scroll wheel will be disabled.
Actually, that's the main reason I hide and lock the status bar from my users - it's far too easy to start typing on one record and accidentally end up typing on another.