In case you are adding a transport into buffer , or importing the transport , but its hanging
then ,
This is a common error, but i saw the same error in other systems
Just first need to check per example tables trbat and trjob in sm30 , if they are empty its safe to detele or to rename the files mentioned in the tplog.
Also another test is to re-execute the rddimpd program , something it will solve the issue, if not we can proceed with the deletion of the file in /tmp
-Thanks
Rabi