I just replaced a 3-way 1100V dimmer switch for a friend. The new dimmer switch works fine, but the other switch does not work anymore. Are you able to help me understand why and how to fix?

Sounds like you may have switches the hot and the traveler on the dimmer. Try swicthing back, is the traveler red or what?

Sorry for the slow response. I believe the traveler was red. Can I simply switch the hot and traveler on the switch that most recently quit working. The original one that I switched has a huge mess of wire that are mis colored n a 4 gang box with all large wattage dimmers. Also, the light switchplate gets really warm. Do you think the circuit or lights on that switch have too much wattage? Thanks for your valuable help.