AC Power type cannot be determined

I have a Dell Latitude D610. Lately, whenever I boot my computer it says this after startup:

"The AC adapter power type cannot be determined. This will lower optimal system performance.

Strike F3 to stop seeing power warnings.

Strike F1 to continue, or F2 to run setup utility."

Also, my laptop always needs to run with the charger plugged in because the battery is almost completely dead. 

Edit

The end of the charger cord that goes into the computer seems to be failing. When the cord is shifted around it stops working. Also, when I enter BIOS setup, the AC listing says "unable to determine" or something like that.