Which depends upon what you are doing. All Linux server editions will serve for web, mail, directory, dns, firewall, and other services. Which you choose depends a lot on other factors such as versions of software that you need to run, who is going to maintain it, how many users will be on the system. We use RHEL for our proxy browsers, supporting up to 800+ users per physical server (dual quad or six core cpus, 72GB RAM, 500GB+ disc space each).

Check out The Linux Documentation Project: www.tldp.org

It may be that some service or driver can't start, but it obviously is not one that you are dependent upon. You can look at the system messages in /var/log/messages* for indicators of what went wrong. It may be that you can just disable some service, or remove an unneeded driver to stop the "nagging".

This is usually due to the repository for an installed package to be unavailable, for whatever reason (network problems, servers down, company out of business). Try again in a few days is my usual advice. If the problem persists, find out the web address of the software provider and see what they say.

I doubt very much if CS6 (the latest and "greatest") works with Wine in Linux. CS5 has plenty of problems, and Adobe doesn't seem too interested in making it compatible with Linux systems. My advice? Run Windows in a Linux virtual machine, and then run CS6 there.

Unfortunately, java installations can be pretty counter-intuitive. If you do this, "ls -l /usr/bin/java" you will find that it points to somewhere else, such as /etc/alternatives, or /usr/java/... - where depends upon the operating system and version. When you install a new Java version, it doesn't necessarily get linked to the defaults in /usr/bin. This is because you can have multiple java versions installed at any time. I know about all of this because I am a senior engineer in a major software organization that uses java extensively, and a number of versions...