The following classes for which you are trying to imort settings do not exist

When importing hardware classes into Custom client settings you will receive error;
The following classes for which you are trying to import settings do not exist. Import the required class definitions and then try to import the settings again.

  

  To resolve this issue, import the inventory class into default client settings instead of custom client settings.
Once the import is successful into default client settings, the classes will be added to the custom client settings automatically.