Hello Nikhilesh
if you have a change request created, it should have the status "To be Executed" and you should be the user responsible for this step.
Now, it seems you are uploading master data in the staging area first and hence this is happening for you. So, once the status of the changerequest is properly set and it comes to you for processing, you can start upload once again.
1. locate and attache the upload file.
2. choose staging area option
3. it will ask for the change request number, in which the change request with "To be executed" should be provided.
this should resolve your issue.
thanks
Rahul