After installing the Canada Post shipping module 1.3.7d on my ZenCart 1.3.7 I am no longer able to access the Module/Shipping section of the admin site. It gives the folowing error message above where the list of shipping options should appear:
Fatal error: Class canadapost: Cannot inherit from undefined class base in /home/userfolder/store/includes/modules/shipping/canadapost.php on line 26

The customer side of the store won't display at all. It gives the folowing message:
"Illegal Access"

I have been unable to find the trouble.

The only other add-on module that I have installed on that site prior to the Canada Post module is the French 1.3.7 module.

Any ideas?