I'm trying to sign a py2exe produced executable with signtool.exe, the standard signing tool.  Executables are signed like this:
signtool.exe sign /a /t http://timestamp.verisign.com/scripts/timstamp.dll "myexecutable.exe"

With other programs (not built with py2exe), this works fine.  However, when I try this with my py2exe generated executable, my application fails to launch and produces this error message:
Traceback (most recent call last):
  File "C:\Python25\lib\site-packages\py2exe\boot_common.py", line 92, in <module>
    import linecache
ImportError: No module named linecache

My application works perfectly without the signing.  I'm using py2exe 0.6.9 and python 2.5.  Any ideas?  Maybe someone could point me to something in the build_exe.py script that I could look at to try to resolve this on my own?