Can they print from other areas of program - report for example? Do they have a default printer setup in windows?

Yes, all other printing functions work on that workstation.

Thank you Caren for the assistance.

Yes, all other printing functions work on that workstation.

Thank you Caren for the assistance.

Then it sounds like either permissions within the program or permissions to the network. I would suggest having this person try opening Timeslips from another computer and testing. If that works, then it is likely something on the workstation permissions. You can try having someone else open Timeslips on the original computer and see if they can print the bills. I would expect not. On the workstation, try running Timeslips as administrator - right click on the icon and run as admin. Further troubleshooting probably requires being logged in. 

Thank you Caren. I was able to alleviate the issue by adding the user's domain account to the security of the local timeslips folder.