About installing automatically: No, and I've never tried that with a .rar archive. Works great for .zip archives, thou. Maybe a setting somewhere else?
I installed it manually, and as far as I can tell it installed flawlessly - maybe I have something turned off somewhere that prevents content plugins from working? Or maybe my translation messes it up?
Anyway, I have a set of template files translated too, but I'm quite interested in those you've made extra for the russian Moz forum - any chance you could make an english translation of one or more of those too, so I can copycat those and maybe use it for our danish Moz forum?
File integrity:
When I pick up the file @ totalcmd, it's 337.339 bytes, CRC wdx_xpiinfo_1.1a.rar AAC321D4
When I pick up the file @ narud, it's 51.889 bytes, CRC xpiinfo.rar 33598413
[EDIT] Just re-downloaded from narud, the file now has the correct size again and works - I have no idea why I got a bad file with same size twice the first time I tried.
[EDIT 2] 
one of those days again... no, both files does not work. The working file I got from wincmd is wdx_xpiinfo_1.1a.rar AAC321D4 (337.339 bytes). This is the only file I got which works.
Keep up the good work.