Unable to set set difficulty level

[jeanoiseau]

I've just installed Civ V on a new machine, using the exact same mods I've used for months on my previous machine. However, when setting up the new game in advanced setup, I'm unable to change the difficulty level past chieftan, there are no other options. After many frustrated clicks the drop down box disappeared altogether. Any ideas? I'm using full CBO mods, really advanced set up mod, among others, but I've used these mods for years in the past with no issues.