editing thread problem

[puregraf]

Hi, im having a problem that when i go to edit a thread in my forum, or anyone that edits a thread , the thread is edited but it shows up like this (example):

<P>test</P>
<P>test&nbsp;&nbsp;&nbsp; </P>
<P>test</P>
<P>test</P>
<P>test</P>
<P>test</P>
<P>test</P>
<P>test</P>

how do I fix this?

thanks