ObjectScript Integration Issue in HealthShare 2016.2 Troubleshooting

Hey, I'm working with HealthShare 2016.2 and trying to implement a custom integration using ObjectScript. I have followed the usual syntax for setting up the integration, but I keep getting an undefined variable' error. Has anyone encountered a similar issue? Here's a snippet of the code I'm using :
set customData = 'Sample Data';
write customData;