It's not possible to say why rc=27 or even which of the 6 REXXs is giving the problem, based on the information you supplied.
But the ISPD117 message simply means that one of the REXXs ended with a RETURN 27 or EXIT 27. That's not a standard return code, so look at the code of the failing REXX and see if 27 is a coded value anywhere. You may have to do some debugging e.g. setting TRACE R.
Oops - the messages do make it clear that the rexx ISPSTART CMD(%NEWC VACZCLHB NC) is the one causing the problem.
But the rest of my comment still applies: you'll have to look inside the NEWC rexx and maybe trace it.