I didn't check it out.As soon as I see the error message I stopped the process.What I did is this.
1.selected a pdf file
2."d" option
3.other devises i.e 4
4.width 800 height 480 output dpi is 267 according to wiki.But I am not sure of input dpi so I kept the same as 267

Now I get the jpeg error.I am very eager to try this.Help me out.