Hi, I recently installed Password Maker 0.8.7 using Firefox 1.5b2 on WinXP. I had the same issue with the backslash missing.
I had set up the extension and changed my passwords. Then when I tried to get a password using the website, it came up with different results. After checking and double checking all my settings I finally figured out that the backslash was missing.
I also thought that maybe I accidently deleted it, so I uninstalled the extension, deleted the passwordmaker.rdf file. And after reinstalling the extension it was still missing the backslash.
Thanks,
~daBron