I just installed thunderbird 1.5 and then I attempted to install some extensions to it and as usual, I restarted it so that they would get installed but still there was "<extension> will be installed when Thunderbird is restarted." on every extension I installed. I tried again but nothing happen. That was yesterday. I usually power off my computer at nights and I tried it again today but yet no success
Edit: It seems that I can change my theme freely but no new themes or extensions get installed