Overview:
When attempting to create a new Inventory Monitoring record from the Inventory Monitoring tab, the following error occurs: Action not allowed. You may not perform that action against this type of object.
Root Cause:
It is not possible to create an Inventory Monitoring record from the Salesforce Inventory Monitoring tab.
Solution:
New Inventory Monitoring records can be created from the My Accounts list, Account Detail page, Inventory Monitoring Related List, and Call Report.
Related Documentation:
CRM Help Documentation: Inventory Monitoring Overview