I downloaded 4b2 on to a new Windows 7 machine. I want to download some "older" addons that aren't yet compatible with 4b2. So I downloaded the Compatibility checker addon, plus manually ensured 'extensions.checkCompatibility.4.0b=false' was set in about:config. When I go to the Firefox Add-On site, I get an error that there was a "connection error" with addons.firefox.com ONLY when I try to download a non-compatible addon (AdBlock worked, for instance, but it's compatible). == This happened == Every time Firefox opened