HELP!! Check engine light. Pulled code 41

My check engine light came on yesterday, I have since pulled the code and got Error code 41 (Heated oxygen sensor - heater circuit) I have no Idea what this means or how to fix it. The car has been sold and the new owner is supposed to pic it up tommorow. I have reset the computer once but the code came back. Any suggestions on exactly what is wrong and how i can fix it? I have a 100% stock 1994 civic EX 5 spd.