What does the "heart beat" symbol/light mean?

I assume you mean the symbol that has a pair blackened circles and then a pulse up and then down below the starting line before returning to the starting line.

That is the paper jam symbol. If the continue light is on (steady) and the paper jam light is on, then you have a paper jam. Press Continue twice to see any secondary error message (this will show where the problem is).

See the manual for the list of the lights that show where the jam is occurring. Different groups of lights will be lit. The manual is available as a PDF at the bottom of this page: http://support.lexmark.com/index?locale=EN&page=product&userlocale=EN . An example: if the Continue, Toner Low and Paper Jam are all on, then the jam is in the fuser area under the print cartridge assembly. For a paper jam, even a small corner of torn paper could be in the mechanism.

In all cases, you should check the entire paper path. When you pull out any paper, grip it so that you can gently pull the sheet straight out. Remove all paper from the output tray. Then remove the paper tray if you are using it. Pull any paper from this area. Press down on the green duplex flap and remove any paper from there Reinsert the paper tray. Open the front door of the printer and remove the print cartridge assembly. Lift the green flap and remove any paper from the area. NOTE: the fuser and the fuser area may be hot. Open the rear exit door and remove any paper from that area. Use a flashlight to check for small pieces of paper that may be stuck. Once all the paper is removed, reinstall the print cartridge assembly and close all the doors. Press Continue to reset the printer.

The page that jammed may be reprinted.

I hope this helps.

Cindy Wells
(please note that frequent paper jams may be a sign of excess humidity in the paper. Put less paper in the tray at each refill and keep the remaining paper in a dry location. If the paper jam light is coming on when no paper jam is present, one or more of the paper jam sensors may be bad. Contact Lexmark for more information.)