I had the same problem with Chinese and received a very honest response via e-mail:
Hi Kevin
I feel like I've got to be honest with you. It's an old tool and we're not very proud of it anymore. It doesn't take advantage of our awesome web index, or all the cool analysis we've done around powerful links. We're working instead to replace it with more powerful link tools. Our newer tools are built to support Unicode, but most of our older ones don't. Sorry about that!
For example, I think you'd be much better off trying our Competitive Link Research Tool (it's in Labs and therefore sometimes gets overloaded, but it's so cool when it works!), or even running your competitors through Open Site Explorer.
www.seomoz.org/labs/link-intersect
www.opensiteexplorer.org
The bottom line is that Juicy Link Finder is unstable and doesn't support Unicode (because we're deprecating it in favor of new technologies), and it doesn't give you very sophisticated results.