Thanks for getting back govpatel.
No - I don't have such a file. If you click on the second link (in my first post) it actually takes you to a sub page of the site which displays just fine. It seems only the main URL is messed up. I can access posts if I type in the long URL to them directly. I can get into admin etc etc. The only thing that's missing is the main page.
I am using Filezilla and have selected "force show hidden files" - but there are definately no index or default HTML files on any level of the domain.
Would a total re-install help? - I'm really lost with this one. I have installed wordpress over 300 times to sites hosted all over the world in the past 4 years (mostly fantastico or similar but dozens of FTP installs as well) never had anything like this happen before.