Corrupted Gecko print.xul?

[Patrick Wiseman <pwiseman@gmail.com>]

Hi, all:

I'm on a 'testing' system, recently updated.

When I try to print a page from Mozilla-Firefox (using either Ctrl-P
or the Printer icon), I get this error:

XML Parsing Error: not well-formed
Location: chrome://global/content/printdialog.xul
Line Number 1, Column 2:

followed by a bit of gibberish.

How can I restore a good printdialog.xul (and how did mine get corrupted?)?

Thanks
Patrick