The same thing has happened to me.
I installed toolsets from brewology that replaced the ones that came with the Evilnat firmware, and messed up the functionality of Webman. I tried going to the backup but they still don't appear. I tried doing a system restore, but still nothing. I tried reinstalling Webman, but it doesn't want to install. It just reboots the system. Should I reinstall the update? my Evilnat firmware is D-PEX. Should I just reinstall it? Because I tried to reinstall webman, and it won't reinstall. The "turn off system option" in the users has also disappeared. Other settings like video settings is not there, neither is the web browser. Do I need to just reinstall the update or do I need to go back to official firmware and re-jailbreak my PS3?