I just inserted a black PG 40 ink cart and theres an error coed 5 indicating that i need to insert a color cart. i set my ink stat to black only and gray scale and it still wont pint

I think you need to have both cartridges in your printer in order to print. If you have put the PG-40 only, the printer can't connect the electric circuit and won't work. Canon's manual explains the error code: the ink cartridges are not installed, or a non supported ink cartridge is installed or the ink cartridges are not installed properly.
So, my guess is either to pop in a Cl-41 and print or, if both cartridges are in, remove them from the printer and gently clean the electric circuit on them with a dry cloth. You can also clean the cartridge carrier. Put the cartridges back in and try printing. If that doesn't work, try holding the "resume" button (triangle in circle) for about 10 sec for each cartridge, that should reset them.

Hope that will help solve your problem!