I had to install dopdf 7 because 5 stopped working (okb). Now only the even pages seem to convert to PDF. These are Sibelius music files.
Please try to completely uninstall the old version from the computer by following up on this tutorial: http://www.dopdf.com/forum/topic/completely-uninstalling-dopdf
After that reinstall the latest build and give it another go.
If you still have issues then let us know from what application are you printing and send us the file in question to email@example.com so we can troubleshoot it.