That error is coming up because a graphic was chosen to display on the receipt, but that graphic file is not available to the software any longer. Either the file was moved or deleted, or for network installs resides on a client computer that the other computer/s do not have access to.

Go into Tools -> Options then into the Reports tab. Click the Show button. You will see an error in the graphics areas at the bottom of the screen.

Your options to fix the issue...
-Uncheck the box to not show the graphics.
-Leave it checked, hit Select and find the graphics file again to reset it it in the software.
-If for a networked install, move the graphics file out onto the network and then use Select to go and find that file.