New error while compiling

Getting a new error while compliing. This project was compiled 2-3 days back. No change since last week. Now, when tried to re-compile with just version change. Getting following error

[GenerateClasses] ERROR: Kawa compile has failed.
[GenerateClasses] ERROR: Can't find class file for Screen 'Screen1'
[GenerateClasses] Task errored in 31.496 seconds

Any ideas?