I know that may sound a little vague, so I'll try and explain a little further...
After being self employed developer for many years I'm now in search of a commercial web developer role. My only experience with servers and hosting is uploading through FTP and playing around with CPanel/WHM a little. The role's I'm going for are web development PHP, MySQL, HTML, CSS type roles, but in recent interviews I've been asked questions about setting up things on the server, that I had no idea what was being said... which wasn't ideal!
Without knowing more than I do, it's hard to explain what exactly I'm looking to learn, but it's basically just the server elements I should know as a web developer? If you're a web developer, do you have any dealing with the server apart from uploading files, and if so, what? Are things like Subversion(SVN) and version control systems often set up by the web development team, could that be what they were talking about?