Adam,
Thanks for all your help. Your question on DPI resolved this issue. The customer had his display setting set to "Large Size 120 DPI". With that all the dialog boxes that you had mentioned were seen cut off.
When I had him change the display setting to "Normal Size - 96 DPI", everything worked fine.
Now my special request to you and your development team is this: Many of our clients and their intended audience are senior citizens where their display settings are set to larger font sizes. Please modify all your dialog boxes so they are resizable. With this change, a lot many questions with dialog box issues will go away both for you and your customers.