Banker Questioned in Enron Criminal Case  HOUSTON (Reuters) - Prosecutors in the first Enron Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=ENRNQ.PK target=/stocks/quickinfo/fullquote"&gt;ENRNQ.PK&lt;/A&gt; criminal trial sought to cast doubt on Wednesday on  a former Merrill Lynch &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=MER.N target=/stocks/quickinfo/fullquote"&gt;MER.N&lt;/A&gt; banker's statements that he was  worried about financial risks from buying three barges from  Enron.