Mark Painter

Can someone give me some pointers on how to generate a file containing two charts overlayed. I can generate a file showing a single plot by passing a filename in the 'new PHPlot' declaration but can't work out how to do the same with multiple plots. Ultimately I need to generate a horizontal bar chart with error bars and the only way I can think of doing this is combining a horizontal bar chart with a horizontal error chart. Any other options I can use would also be very useful. Many thanks.