Hi there, @dpringle53. I can help you fix the error message you're getting while doing your inventory.
To isolate the issue please make sure that the addresses linked to your customers or vendors which are associated with your inventories are correct. A problem with the address may result in this error message.
If everything is in place yet the error continues, I suggest reaching out to our Support Team for further assistance. Our designated team can look into your account securely and review the root cause of the error. For the support's contact information, open this link: Contact Payments or Point of Sale Support.
For more tips about doing physical inventory in QuickBooks Point of Sale, you can open this link: Perform a physical inventory.
If you have any other questions about your inventory transactions, let me know by adding a comment below. I'm more than happy to help. Wishing you a good one!