GP: Creation of process for uploading file with approval or a rejection

Problem: It is necessary to organise process of uploading files in KM repository with approval or a rejection.

I have created process with two callable objects.

1. File Input

2. Interactive Form/File Approval

Has grouped structure "File"

In Runtime, during object performance "Interactive Form/File Approval" there is an error:

com.sap.tc.webdynpro.services.exceptions.WDRuntimeException: pdfSource of InteractiveForm UI element should be populated with pdf binary content in USE_PDF mode

It is one problem, the second problem consists in that how to organise a folder choice where the file will be loaded.