A .pdf file on disk? Matlab afaik doesn't have a packaged printer driver for pdf files; you have two choices--
1) use open to open the file in pdf viewer and then use ActiveX to print or
2) install a freeware or Adobe pdf virtual printer device to which you can then direct print towards by using printopt
There is a third that's a slight variation of 2) -- submit an OS print command via system -- essentially just execute the command that would be given to printopt to send a file to the virtual printer above.
