I downloaded my old application with the new Interact 7 to my PA2 and when the PA2 tries to start all I see are vertical stripes.
The early displays only supported 16 color mode and the new displays only support 256 color mode. Running in the wrong mode will cause the display to only have vertical stripes.
Open the application in Interact and select File from the Interact Application Manager toolbar then select - Interact Settings - Run Mode Display and change "Number of colors:" from 16 colors to 256 Colors.
Download the changed project and reboot the PA/PA2 etc...