How do I resolve the "JMR611I PKRDALS2 R/C = 02100000 - DSN = your.DAILY.JMRYYDDD" messages ?

This happens when I run the archive job. Sometimes you will see a resulting S001 abend as well.

Release: ESBJMR99000-4.6-Extended Support Basic-for CA JMR
Component:

The 0210 indicates a shared allocation request was issued on a dataset that  

that is in exclusive use elsewhere.                                          

Possibly a full volume backup in progress or another job using the files from another system. The enqueue that is required must be resolved.