Why do I receive the following error during installation: "Missing Organization Feature: RecordType"

After clicking the Get It Now button from the AppExchange for Soapbox Mailer, some organizations may find that they receive an error message during the installation process saying that they cannot complete the installation, including the following one:

This app can't be installed.
There are problems that prevent this package from being installed.
Missing Organization Feature: RecordType

If you receive this message, it typically means that you do not have access to Record Type functionality in Salesforce because you do not use the Enterprise Edition of Salesforce. Unfortunately, the Enterprise Edition is required to use Soapbox Mailer.

If you are using the Enterprise Edition of Salesforce, please contact our support team for further assistance.