Delphi+ArcGISEngine的一个小问题

<P>一段画点的代码</P>
<P>var  Fclass: Ifeatureclass;</P>
<P>  ftr: Ifeature;</P>
<P>.................</P>
<P>  Fclass.CreateFeature(ftr);</P>
<P>  if ftr = nil then<BR>  begin<BR>    showmessage('ftr=nil');<BR>    pWorkspaceEdit.StopEditOperation;<BR>    pWorkspaceEdit.StopEditing(true);<BR>    exit;<BR>  end;</P>
<P>......................</P>
<P>执行到Fclass.CreateFeature(ftr);提示</P>
<P>[Error] Unit1.pas(134): Types of actual and formal var parameters must be identical</P>
<P>请问高手何故？</P>

ftr没有被实例化?