Multi-lingual website displaying garbled text after running successfully for several months

I have a multilingual website. www.findinjp.com.

It was running fine without any problems with English and Japanese. I haven't checked on the site or used it for several months and when I came back to it to do some updates I see that all the Japanese text is coming up as corrupted text. Can someone help me with this?

Why did this happen, is there something I can do to fix it? Do I have to go back into each menu, taxonomy and node content and rewrite the Japanese text?

Thanks!

Josh