pickle error - 'module' object has no attribute'_reconstruct'

[Skip Montanaro]

Saw a new-to-me error today when trying to unpickle a moderately large
object (about 500k):

AttributeError: 'module' object has no attribute '_reconstruct'

Google turned up nothing as far as I could tell, "_reconstruct"
doesn't appear in the docs and pickletools.dis() was happy to
disassemble the pickle. This was with Python 2.4. Any ideas about
the cause of this error?

Thx,

Skip Montanaro