IE7 Window Close Alert solution:

Solution 1: http://support.microsoft.com/kb/911328/
Solution 2: edit default.aspx, modify:

if (window.name != "MSCRM_MAIN")
{
  //var oMe = window.self;
  //oMe.opener = window.self;
  //oMe.close();
  window.open('','_parent','');
  window.close();
}