I have been running the same configuration for the last few years or so, I have an XP PC Land Desktop Companion 2009 and an HP DesignJet 500 connected with a USB cable.
I had not been able to send more then one sheet or copy of a sheets to the plotter for some time, someone suggested I just re-install the plotter and see if it fixes the problem.
So I deleted the HP DJ 500 in windows and re-installed it with the driver from HP. It seems to work fine untill I try to plot an existing drawing. I can select the new plotter and preview it, but if I try to plot or save the drawing LDC 2009 freezes or says it encountered and error and closes.
If I make a new drawing from sctratch (I have just tried something simple and quick) it will plot.