Here is a self explanatory example of the problem:
  $ exo-open "http://wyborcza.pl/biznes/1,99154,6814199,Jak_nie_kupowac_funduszu_w_worku.html"

This gives the following link in the Firefox address bar:
  http://wyborcza.pl/biznes/1%2C99154%2C6814199%2CJak_nie_kupowac_funduszu_w_worku.html
which of course results in Error 404 (Page not found)

The expected behaviour is to not change commas ',' to %2C, but to pass them literally.

Thanks,
/Adam