Thanks. I guess the "installation folder" option is for the silent installer then and doesn't affect the addon? Vanilla firefox works but I couldn't get ayakawa's to work. I installed MS visual c++ 2008 sp1 redistributable package like you said in the first post and the windows script 5.7 installer said that it wasn't needed. After installation either using the addon or the silent installer, it would give me this error when I try to start firefox: XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 34, Column 1: <window id="main-window" ^ Anybody else have this problem?