LukeSettle, there is already an active thread for Anki, where Resolve answers many of the questions and troubleshooting from Anki users. Anki discussion is here.
Just looking now, the "Anki" thread is third down in this sub-forum category ... please browse the forum a bit before posting new topics.
As for your problem, you most likely didn't install the Japanese fonts on your computer. If you look at the bottom of the "learn more" page on the main RtK site (click the logo at the top of the page), there is a link to a page detailing how to install the fonts on your PC.