Ok first off mame32 doesn't exist... it hasn't in years. Back in the day mame32 had a gui and the name was used to differentiate it from the dos version. Since the DOS verison no longer exists.....
Do you mean mameui? Or the 32bit build of mame?
Ok things to check.
First off make sure the mouse is actually enabled. If you are using the ui version I'm sorry I don't have a clue how to set things in it as I haven't used a ui version of mame since 1999. In the mame ini the settings you need to change are in the "# CORE INPUT AUTOMATIC ENABLE OPTIONS" section. Any device you want to be controlled by your spinner (paddle, dial, ect) you need to set to "mouse". That'll auto enable/disable the mouse for you depending upon the game, which should save you some headaches.
You can also flat out enable the mouse for all games, but I don't recommend that anymore.
Secondly when you are in the game itself understand that you should NOT pause the game when re-mapping the inputs. It DOES make a difference!
Thirdly if multi-mouse is enabled, only the specific mouse you are using when you map it will work. This doesn't appear to be the issue, but keep that in mind.
If none of that works research how to make ctrlr files.