I can't install Steam or any other software. Is there a problem with dpkg error - how to solve this?
The errors in your question seems not related to Steam.
To fix errors with PHP packages run
sudo apt-get update
sudo apt-get install -f
sudo dpkg --configure -a
sudo apt-get dist-upgrade
Also please note that you do not need sudo when you are already root user. Being root for long time is dangerous, then use sudo while being normal user.