Why can't I post international characters in Pownce comments.

I've been having problems posting comments via the browser version of Pownce. During a long thread of postings from multiple users (the FNPDC on 3/14) I attempted to submit comments with international characters. Those comments with non-standard characters wouldn't post, but others went through without problem. I tried cutting and pasting special characters from comments posted by international users, but those wouldn't post either. So I'm wondering if there's something with the encoding settings of my browser (I've tried Firefox and Opera with the same results.) Any suggestions would be appreciated. Thanks!