Navistar Profit Rises, But Shares Fall  CHICAGO (Reuters) - Commercial truck maker Navistar  International Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=NAV.N target=/stocks/quickinfo/fullquote"&gt;NAV.N&lt;/A&gt; reported higher quarterly earnings  on Thursday, but its shares fell more than 5 percent as the  market focused on lower-than-expected profit from its core  manufacturing operations.