You may not be on the exact same distribution number as the author of the installation was on...
For example, the author of the script could have made it for a 64bit Linux, and you are on 32bit.
Or you may be on a the latest version of the distro,( Fedora version X vs Fedora version Y ) while the author was not...make sense ?
OR the packages may exist for your version, but you have not enabled the repository.
Get on the same version,look for equivalent packages that provide the same functionality on your version, or enable the repository they are in.
Clear as mud eh ?