PTI invoicing error: This happened for Field Name: G/L Account

If receive the following error when invoicing:

Invoicing completed with some errors:
Invoice: Invoicing failed due to the following error:
An error occurred while importing!
This happened for Field Name: G/L Account

The error is because your Peachtree itself is not set up yet.

The default accounts for Peachtree inventory items have not been set up in Peachtree. Because of this there is nothing for Peachtree to use as the GL Account and thus the error message is thrown when you try to use PTI to invoice into Peachtree.

In Peachtree go: Maintain->Default Information->Inventory Items. Look at the GL Accts/Costing tab and review the defaults that are set.

I included an example screenshot below which is from a sample company.

In Peachtree go: Maintain->Default Information->Inventory Items. Look at the GL Accts/Costing tab and review the defaults that are set.
The window should look similar to the one below which is from the sample company.
Make sure that there is something specified for for each in every field and every row.