FAQ - QuickBooks Desktop: Billable Transactions Require an Associated Customer
This error messages indicates that some of the expenses on the report that you are trying to export are flagged as "Billable" but have not beed coded with an associated customer/job.
To resolve, open the report and select a customer/job for each billable expense:
If you do not see a list of Customers/Jobs to choose from when editing your report, you may need to enable them in your configuration settings.
Once all billable expenses have been properly tagged, try exporting your report again.