If you don't completely understand the reasons for the permissions of the files on your system, don't change them.
Generally speaking, files outside your home directory or
/tmp or designated directories for data should belong to system users, not to you.
Furthermore, you should not write under
/usr, with the exception of
/usr/local: this is reserved for your distribution or package manager. If you want to install a program system-wide, install it under
That installation script looks like it's trying to install in the wrong places. If it tries to copy things to
/usr/lib, it's broken. Don't use it. Look for a package for your distribution, or for a better installation script, or better installation instructions. Again, if things end up in
/usr/lib (as opposed to
/usr/local/lib) without going through a package manager, the installation process is broken.