500 Error occurs when customer saves address with cartridge disabled.

[chrismshea]

Issue

When Subpro Enabled is set to No in Custom Preferences, and a customer attempts to create and save a new address from My Account the following occurs.

• address is saved
• customer is left on address form
• 500 error is found in console

Expected Result

The address should be saved as normal and customer returned to list of their addresses.

Steps to Reproduce

In Business Manager

• In Business Manager navigate to Merchant Tools > Custom Prefreneces
• Click on the subscribe-pro id
• Set setting Subpro Enabled to No

On front end

• Login or create a new customer account
• Under Address Book click Add New to create a new address
• Complete the form, and click Save
• The form will not appear to save
• view the developer console and you should see the following 500 error