Yum/sosreport fails with error - AttributeError: 'module' object has no attribute 'pickle'

Issue

I am running into an issue when I try to run rhn_register and any yum commands on my RHEL 5.4 x86_64 server. Here are the errors that I am getting:

# rhn_register
'import site' failed; use -v for traceback
Traceback (most recent call last):
  File "/usr/sbin/rhn_register", line 14, in ?
    import os
  File "/usr/lib64/python2.4/os.py", line 693, in ?
    _copy_reg.pickle(stat_result, _pickle_stat_result, _make_stat_result)
AttributeError: 'module' object has no attribute 'pickle'