[exim] Spam error

Hi

I will probably be told this is the wrong user community to ask the question
but perhaps someone can point me in the right direction since I think this
is a spamassassin issue rather than an exim issue

When I learn spam with SA I get the following error:

"Parsing of undecoded UTF-8 will give garbage when decoding entities at
/usr/share/perl5/Mail/SpamAssassin/HTML.pm line 182."

I would like to understand what this means, is it a big problem and how do I
correct it ?
any pointers as to who I can ask would be much appreciated

Kind Regards
Hill Ruyter