Example file mailer.jsp, lines 12-21 must look like shown below, without 
newlines before the closing tags. Otherwise the newlines get into the message, 
where the first one is interpreted as the start of the body. Subsequent lines 
would then become part of the mail body.

<mt:setrecipient type="to"><%=request.getParameter("to")%></mt:setrecipient>
<mt:from><%=request.getParameter("from")%></mt:from>
<mt:setrecipient type="cc"><%=request.getParameter("cc")%></mt:setrecipient>
<mt:subject><%=request.getParameter("subject")%></mt:subject>
<mt:message><%=request.getParameter("message")%></mt:message>