The error is caused by IOException thrown in

java.awt.Font.createFont( Font.TRUETYPE_FONT, fontBytes )

call and usually caused by an attempt to load a custom font, which is not fully compatible with Java’s font subsystem. Usually the standard arial.ttf (for example from our sample fonts.jar) causes no problem.

Can you reproduce the problem when run PD4ML in command line mode?

See http://pd4ml.com/html-to-pdf-command-line-tool.htm