Hvad - Exception occurred

Dette script har kørt helt fint lige indtil idag

function findNiveau(id, level)

  dim rs
  level = level + 1
  SQL = "SELECT * FROM navigation_menu WHERE NAV_PKEY = " & id
  set rs = Connect.Execute(SQL)
  if Cint(rs("nav_parent")) > 0 then
    level = findNiveau (rs("nav_parent"), level)
  end if
  findNiveau = level
  rs.Close

end function

function UpdaterRecord

set rs = connect.Execute("Select * FROM navigation_menu ")
if not rs.EOF then
Do until rs.EOF

Response.write "NAV_PKEY "&rs("NAV_PKEY")&" er på niavu " & findNiveau(rs("NAV_PKEY"),0) &"<br>"

SQL = "Update navigation_menu set NIAVU= " & findNiveau(rs("NAV_PKEY"),0) & " "
SQL = SQL & " WHERE NAV_PKEY= "& rs("NAV_PKEY")
Connect.Execute(SQL)


rs.MoveNext
Loop
else
'====ingen felter
end if

end function

Nu får jeg fejlen
Exception occurred i linie:

if Cint(rs("nav_parent")) > 0 then

hvad går der galt ??