[Xmonad] run-xmonad.sh

I've started using the run-xmonad.sh script, but I've found that only one of the menu bars start up correctly. I've recompiled dzen with xinerama support, and set the status bars to show up at the left and right of one of my screens. The menu that reads from the pipe for the workspace status works nicely. However the other statusbar (which I can start from a terminal by hand, and see it show up doing its thing correctly) doesn't show up. Any ideas all ?