It depends on the error message, obviously.  Some are:

    unable to load display mode, rnid = 196614, errno = 22
    Failed to unbind rn from clip, rnid = 3,errno = 22
    bogus window id in rrm request type(2)

  These are messages related to the communication between the rrm layer
  in the kernel and the X server.  The messages usually occur when a GL
  window is being destroyed in a sequence that the X server did not
  expect.  They are quite benign.