Uninstall the Spellbound extension using the extension manager. Download each component for spellbound separately, i.e.don't install, but right click on the below links and select "save link as" and save them to your desktop.
Now, open your extension manager(Firefox > Tools > Extensions)and minimize it to the taskbar. Go to your desktop and drag each item to the Extensions manager tab that's been minimized to your taskbar. When you drag each item to the extensions tab, the Extensions manager should open and allow you to drop each item onto it.
Manually installing the extension components this way may get it to work, but also the link for the win32 lib is a version that was produced to cure some bugs.
HTH, and you can follow my rambling instructions, dagwoood.