cannot print attachment

[alunp]

When I have an attachment open and click on print or print preview the "printing" box appears telling me that it is preparing, but the document title is blank and the cancel button is greyed. Nothing else happens - no sign of activity on the hard disk and eventually I have to close the box by clicking on the top right corner.

If I save the attchment to a directory (this one is an EML file) and reopen it in Thunderbird then it prints normally.

I can print messages as normal.

Any ideas how to solve this so that I can print attachments directly from the program?

Thanks

Alun