No paperjam,red light + paperlight flash as soon as I click on 'print'

SOURCE: paper light flashes red...

I found just doing this one simple thing sorted the problem.

First take off the front cover. Pull the tabs on the side. Pull out the big toner and cartridge. Do you see the blue tab on the top shaped like an arrow/triangle? Slide the tab from right to left - reinsert toner close door.
Hope it works for you

JPW

SOURCE: Flashing red light - no paper jam

I had this problem and couldn't figure out until I opened the front, pulled out the toner cartridge and found a paper jam.  Removed it and now I have the green light.

SOURCE: won't print. blinking red paper light flashing

This usually means your printer is out of paper or there is a paper jam somewhere.

SOURCE: Red error light is flashing on Brother HL-2040

http://welcome.solutions.brother.com/BSC/public/us/us/en/faq/faq/000000/000100/000070/faq000170_006.html?reg=us&c=us&lang=en&prod=hl5240_all

Hope that helps,

Tiger720

SOURCE: Error flashes

I've read several posts on the "red flashing error light" on the Brother HL-2170W. I have mine hooked to a mac - but I'm sure the pc is the same way. One other previous post said look for a paper jam. Well, there are only a few places to look...and I found no paper jam UNTIL I removed the toner cartridge and looked UNDER the cartridge and VOILA, there was a paper jammed underneath. I removed it and I'm back in business. Normally paper jams when it is almost out of the printer and you can locate it by opening the back of the printer. Well, this one was "sneaky" and hid completely underneath the toner cartridge.
Hope this helps someone else...