ShiftPWM - Error in project

I have a project that I already loaded onto one chip (ATMega328) on an UNO board. I moved computers and am trying to get it to work again, however, I am coming up with an odd error:

MyProject.cpp.o: In function ShiftPWM_handleInterrupt': C:\Users\Andy\Downloads\arduino\arduino-1.0.1\libraries\ShiftPWM/ShiftPWM.h:124: undefined reference toShiftPWM_balanceLoad'

It is a pretty basic program and I did load the ShiftPWM into the Libraries folder. There is nothing inherited that is not in the libraries folder at all. This may be a new version of ShiftPWM, though... I had last loaded it about a year ago - Can't imagine why that would make a difference, though.

C:\Users\Andy\Downloads\arduino\arduino-1.0.1\libraries\ShiftPWM/ShiftPWM.h:124: undefined reference to `ShiftPWM_balanceLoad'

Were you using arduino-1.0.1 on the other computer?

I honestly have no clue at all :( I don't have a backup of that computer anymore. Was whatever version there was from almost 1 year ago.

I loaded the only version (1.0) that could have been on my old PC. Didn't make any difference :(