I hope this helps you . You have cleaned cache from system->cache management right? Also some extensions require you to logout and login in backend otherwise they give you 404 page. Also try to look in system->configuration->advanced->disable module output. You can see all installed extension on your installation.
firefox add-on sdk: previously removed and reinstalled add-on doesn't work but shows up as installed in add-ons manager
I wish did fix the issue. copy "java.exe" and "javaw.exe" file from "C:\Program Files\Java\jdk1.8.0_05\bin" to "C:\Windows\System32". Because sometimes during installation or updation these files are not reflected correctly. Hope this helps.
While running android AVD manager it shows error "HAX kernel module is not installed!"
I wish this help you Create emulator in CPU/ABI in ARM, this error only exist for the Intel processor. If you want to create AVD CPU/ABI in Intel for this process. Make sure you have instaled HAXM installer on your SDK Manager.