If you have such a dump at that line, the only possibility is that <L_LINE> was not assigned to a memory block before this statement.
As far as I can see, there is only one possibility where <L_LINE> is assigned is at the statement ASSIGN dref->* TO As this is included in IFs and LOOPs, it may not occur, so you must absolutely decide if that's normal of what you want to do in that case.
You may test whether <L_LINE> was assigned, by using IF <L_LINE> IS ASSIGNED.