This is my nightmare....I have a box with two light switches. Light switch on left controls kitchen light. Switch on right controls dining room light. (this box also supplies power to some stuff in basement as well). Yesterday we installed a new dining room fixture that takes dimmable bulbs so i got a dimmer switch that works with led bulbs. I opened up right switch. The switch had 3 black wires......so I wasn't sure which one was the hot line...so i picked up a tester and found my line.
My dimmer switch has 4 wires coming from it...1 black, 2 red, 1 green. So I hooked up the black one to the black power line...the two red wires I hooked up to the other two black wires coming from the box...hooked up ground wire....put everything back in...turned power back on....came upstairs to test....turned on right switch...yes...lights up and dims.... And then...I turned off the dining room light ....and the kitchen light came on....wtf? ok ok.....so I decide to swith the red wires around.....and same thing......lights come on but it's all messed up.....then i find out that when i turn on things with this switch...it turns them off in the basement.....so i've obviously messed up the wiring.....thoughts? Perhaps I got the wrong dimmer switch?

 

dimmer switch is dvcl-153-wh

 

If you only messed with the wires to the switch it is possible that some wires became loose when you were moving wires around. Check all the connections in the box to make sure they are tight.

The switch you replaced was a 3-way. According to directions I found online, the red is your hot and the black and red with a stripe are the travelers.