Most likely a failure to read the warnings in the installation manual.
As Stream101 mentioned, if you run with --deps (or --shoutcast-all or --icecast-all which imply --deps) Centova Cast will automatically run yum/apt to install any missing dependencies. The installation manual explicitly states that you shouldn't run with --deps if you're running any other control panel/etc on your server, and that you should check your dependencies manually if that's the case.
The quoted error messages show that you're using PHP 5.3 or greater with a script that was designed for PHP 5.2 or earlier. Most likely your PHP packages got updated as a result of CCv3's installer trying to update mysql-server, because PHP depends on mysql-common (a common dependency with mysql-server).
In any case, to be clear, all Centova Cast did was to ask apt or yum to upgrade your server (at your explicit request) to the latest packages provided by the Debian/CentOS maintainers, which (if you want to run a secure server) you should be doing anyway. CCv3 itself did not modify/alter anything, and the error messages you're seeing are simply because you're using an outdated script with a now-modern PHP interpreter.
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