That's probably a problem with your computer or the program then. I know my PSP7 gets tired if I'm using it too long, and when I try to load something like brushes or shapes or gradients it'll error out, soooo...either mess with your settings (wouldn't know exact) or save the whole thing as a .psp, quit, and then open it and try to draw the wires then.

if it still doesn't work, you could try doing a freehand line, anti-aliased.

..and if THAT crashes too, you might want to check out troubleshooting.