Forum OpenACS Development: Re: Charset difference with NaviServer and OpenACS 5.9:

It seems like an encoding issue while storing the data. Not sure if you have had a chance to try encoding convertfrom (or convertto) utf-8. If that does not work, the following might help (off the top of my head):

binary scan $somebindata a* somevar

along with:

binary format a* $somedata

That said, there is a nice article on charsets and unicode by Joel Spolsky: