LabVIEW 6.1 can not handle more than 555 top level controls (controls or
indicators with terminals) in any single VI. If you have more than this,
the VI builds a corrupt description of the dataspace and once saved, the
VI cannot be loaded successfully. It may not always fail in the same way,
but it will fail. A workaround is to place controls into clusters. These
clusters only count as a single control/indicator.
Marcus Monroe