The error mentioned below comes up when our order entry staff is adding a tax code to a line on a sales order that has a project attached to it and a product variant attached to the project.

IS NOT A VARIANT OF xxx (where xxx is our item number).

I have never used product configurator and am not sure what could be causing this error. Any help would be greatly appreciated!

I am afraid my answer is a bit vague but it might give you a clue.
We get this error when (occasionally) something goes wrong with the product configuration process and the line is not/can not be saved.

Does your error still occur if the user saves the line first maybe?

The record is already saved. If we go to the line and try to change the tax code, Baan accepts it (BaanIVc4). When we try to save and exit (or save) the error appears. We then have to undo or exit without trying to save the data for it to revert to the original field value, then we can exit the session.

Not much help but:

For some reason we can't change our tax code on the SO line.

In the table tdsls041 there is a tax country and a tax code. Our SO lines form displays the code but not the country. Maybe that is why we can't change it at all - but it could explain why you can't save a change.

Maybe you have a 3rd party tax software or extension that is intercepting this ?

No, there is no third party software for any of our taxes.

I may have to log a case with Baan.

Thanks for your suggestions!