In InDesign, I have a file that's RGB (and I set the 'intent' as web, so the program is reading it as an RGB document-I could see it), but it's printing CYMK. what printer settings do i have to change?
You can't print RGB. The colour range and the way that colours are constructed are so different between screen and print, that any print will always be CMYK.
We have a great Q&A about the difference between the two colour spaces right here. Go and read up on your colour space theory right there!