Autodock - Integral Charges?



I just started using autodock, and I'm getting an error message about
 residues
 not having integral charges.  Does this mean that the charge on each peptide
 of a receptor has to be an integral value of -1, 0, 1 or something along those
 lines?  As well, does anyone know how to avoid this problem, as it occurs
 whether I calculate the charges in AutoDockTools or using another program
 (Molecular Operating Environment - MOE).  Any help or suggestions are
 appreciated.
 Thanks,
 Robert
 Robert Flight
 Department of Chemistry
 University of New Brunswick
 e-mail: L72K6 -8 at 8- unb.ca
 tel: 506-461-5760