Web site with problems (with Linux browsers only)

Hi, a friend of mine is running a Joomla based website http://www.DeutscheInMelbourne.net . The first page renders fine on Windows and Apple devices but has a full page of spam gibberish <a href>'s to the most wanted items if I believe in spam) before the header menu starts (so I have to scroll down to see any useful content) I tried on two Ubuntu machines running Ubuntu 12.04, and tried Chrome and Firefox, always with the rubbish in it. Stranger, it does not even appear in the page source if I look at it using Windows or Apple machines. I did not look at the server yet (and my friend isn't an IT expert) but I find it that weired that I don't have a slightest idea what the cause might be. Any ideas? Thanks for answers Peter