Roy, Indonesia is not the only country that has visa on arrival. Milan posted that she got a visa on arrival into Korea, however she was accompanying her husband.
Greg, the in's and out's of getting a visa into Korea for your girlfriend is a question for a Korean forum, not a Bali forum. There are few members here who have experience in your exact situation, even Milan was accompanying her husband.
I suggest you try Thorn Tree where lots of posters have direct experience with visa issues into Korea.
