About installing the package

Hi, Thank you for all your contribution on PEAR. I've faced a problem when i try to install pear packages using command line under windows. I've installed some pear packages through this method successfully few days before, but i've discovered that i can't install any packages now and when i typed, for instance, "pear install vfs", it showed me "no signature found for package.info(string, string, bool). I'm not sure what has been happened. Could you please tell me what's the problem and i'm looking forward to hear your reply. Cheers, Roger