Hm, if nobody answers, it probably means that nobody has come across this before :-)
But seriously, CKNSERVE and CKX (the command executor) try to allocate a temporary dataset. It is attempted using the default (probably blank) esoteric unitname. For most customers that seems to work fine. It's unclear why that fails in your environment, maybe ACS routines?
Probably the best way to continue is to open a case with the support team.
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Guus Bonnes
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