I get an error – 10 message or error – 3 when I try and print a drmz or drmx file

This indicates that although printing is permitted, the printer type you have is not supported by the Javelin software for the document you are trying to print from. There are two main reasons this might occur – the first, and most likely, is that the publisher of the file has not selected the appropriate option for printing when generating the file. The recommended settings are provided in the article located here. It is also possible that your printer is indeed not supported. In either case please contact the document publisher for assistance, including your log file where appropriate (access from the Javelin File menu).