Error: sudo: must be setuid root
1.chown root:root /usr/bin/sudo
2.chmod 4111 /usr/bin/sudo
3.If this doesnt work make sure that the commnd used (eg:sudo gem list) is added to user’s permission at /etc/sudoers and check the command path is correct say gem can be on /usr/local/bin/gem or /usr/bin/gem. The same can be happened with other commands too. You may find the path of a command by $which gem (the command name)
