py2exe can't import packages that should be available (simplejson)

In my py2exe build script, I was specifying a few modules to be imported that for some reason would fail to import. I could import these from the python prompt, but the build script would give the following:

running py2exe
*** searching for required modules ***
Traceback (most recent call last):
  File "setup.py", line 235, in 
    console=[ 'runcm.py' ],
  File "C:\PYTHON25\LIB\distutils\core.py", line 151, in setup
    dist.run_commands()
  File "C:\PYTHON25\LIB\distutils\dist.py", line 974, in run_commands
    self.run_command(cmd)
  File "C:\PYTHON25\LIB\distutils\dist.py", line 994, in run_command
    cmd_obj.run()
  File "C:\Python25\lib\site-packages\py2exe\build_exe.py", line 243, in run
    self._run()
  File "C:\Python25\lib\site-packages\py2exe\build_exe.py", line 296, in _run
    self.find_needed_modules(mf, required_files, required_modules)
  File "C:\Python25\lib\site-packages\py2exe\build_exe.py", line 1297, in find_n
eeded_modules
    mf.import_hook(mod)
  File "C:\Python25\lib\site-packages\py2exe\mf.py", line 719, in import_hook
    return Base.import_hook(self,name,caller,fromlist,level)
  File "C:\Python25\lib\site-packages\py2exe\mf.py", line 136, in import_hook
    q, tail = self.find_head_package(parent, name)
  File "C:\Python25\lib\site-packages\py2exe\mf.py", line 204, in find_head_pack
age
    raise ImportError, "No module named " + qname
ImportError: No module named simplejson

Apparently the problem has to do with that the modules in site-packages stored as zipped eggs would not import. Simply unzipping the simplejson egg contents so that the simplejson directory was in the site-packages directory solved the problem.