Cannot load data using Data Loading(file) activity in Workflow

I am new to Campaign Classic and I am trying to import the data to a schema using workflow. I was instructed to use the Data Loading(file) activity to load the data to the server. I am facing issues when I configure the Data Loading activity. I chose the file, that needs to be loaded, in the 'Sample File' section of the activity. And in the 'Name of the file to load' section I chose 'Update a file from the local machine' option. Later I selected the same file to load and clicked on 'Upload on server'. The prompt showed the upload was successful and if I click OK there will be a pop up telling - the upload is still under process and if I want to stop it. Basically I can't come out of the Upload to server prompt with out clicking Cancel. And once the prompt is closed it shows the files is still not uploaded to the server. I have attached the screenshots along with the logs. Please help me resolve this issue.

Ps: I am using Campaign Classic Training instance.