Using Jumpers wires in an Electronic design
RS-232 will be running comparatively slowly. Provided the MAX232 is properly decoupled and the connections are kept short the number of jumpers shouldn't matter. You probably have a wiring error with the capacitors; I prefer the MAX202 to the MAX232 as the former uses 100 nF ceramic capacitors. I never use Veroboard and often make my own prototype PCBs at home, I have a useful little board with a MAX202 on it that I can connect to anything that needs RS-232 conversion.