Receipt acticity setup with tax applicable generating an error

Good Day All

I have a Receipt activitiy defined to allow for tax accounting when a receipt write off is performed. The setup for this activity is as below:

Now when this is used in a receipt activity it produces an error on saving the transaction.

I cannot find any hits on Oracle Support or Google. Does anyone have any idea. Is my setup incorrect maybe? Or could this be a required patch?

Any help would be appreciated

Thanks

Chez