Add Multiple File Upload Components Dynamically

I am trying to implement loading of multiple files through SAIL. I used the code from link "forum.appian.com/.../recipe_add_multiple_file_upload_components_dynamically.html". But when I upload the file, I am geting error

17:55:12,668 INFO [stdout] (ajp-/0.0.0.0:8009-1) com.appiancorp.process.expression.ExpressionRuntimeException$AppianExceptionWithRootCauseProvider: Expression evaluation error in rule 'ucmultifileuploadrenderfield' (called by rule 'test') at function a!applyComponents [line 538]: An error occurred while executing a save: Expression evaluation error in rule 'ucmultifileuploadresizearray' at function 'remove' [line 19]: Invalid index (1) for list: valid range is 1...0 (APNX-1-4198-019)

Can anyone guide how can I fix it?

Thanks

OriginalPostID-266319