Calculating inventory error

I am getting an error when calculating inventory in the Phys. Inventory Journal.

ie. The field unit of measure code of table item journal line contains a value (TABLET) which can not be found in the related table (Item Unit of measure). When I check in the Item Unit of measure table the value “TABLET” ACTUALLY EXIST!!. any other suggestions are welcome. Thanks.

What is the error ? Can you paste the screenshot here?