ABEND S0C4 at the very start of all CFT modules, all versions
This problem is created by a change in the default addressing mode of IHAPCCA, accessed to get the CPU serial number.

Note: the ABEND copied bellow is for information only as the relevant information can differ depends or the exact CFT version is installed.

10.02.52 STC27974 ---- FRIDAY,    14 JAN 2011 ----                                                                            
10.02.52 STC27974  IEF695I START CFTMAIN WITH JOBNAME CFTMAIN IS ASSIGNED TO USER CFTMAIN, GROUP $STCGRP                  
10.02.52 STC27974  $HASP373 CFTMAIN  STARTED                                                                                  
10.02.52 STC27974  IEF403I CFTMAIN - STARTED - TIME=10.02.52                                                                  
10.03.32 STC27974  IEA995I SYMPTOM DUMP OUTPUT  055                                                                          
  055             SYSTEM COMPLETION CODE=0C4  REASON CODE=00000010                                                          
  055              TIME=10.03.06  SEQ=10710  CPU=0000  ASID=00E2                                                            
  055              PSW AT TIME OF ERROR  078D2000   0003A2AC  ILC 6  INTC 10                                                
  055                ACTIVE LOAD MODULE           ADDRESS=00007000  OFFSET=000332AC                                          
  055                NAME=CFTMAIN                                                                                            
  055                DATA AT PSW  0003A2A6 - 10085810  0208D20B  B0401004

The issue is related to the PCCA that can be above 16MB (31b by default is assume since Z/os 1.12)
It is fixed with the Patch 1 for version 2.6.4 SP2
It is also fixed with the SP11 for version 2.4.1

Note that the SP2 from version 2.6.4 can be applied over any older 2.6.x version without having to apply intermediate SP or Patches (even the upgrade pack 2.6.x to 2.6.4 is not needed)

Workaround: change Z/OS IPL parameters to relocate the IHAPCCA in 24bits storage.
''
CBLOC [VIRTUAL24(structure1,structure2, ...)] [VIRTUAL31(structure1,structure2, ...)]
    VIRTUAL24
       Provides the names of structures to be located in 24-bit virtual storage.
    VIRTUAL31
       Provides the names of structures to be located in 31-bit virtual storage.

For structure names:
   IHALCCA & IHAPCCA

It mean setting CBLOC VIRTUAL24(IHAPCCA) in member DIAGxx of the PARMLIB to force the PCCA in 24b

''

Note1:
The following temporary workaround should also works:
1) Create a LINK EDIT JCL derivates from the B20LINK one
2) Just use the following statements as SYSLIN:
 INCLUDE SYSLMOD(CFTMAIN)        
 ENTRY CFTENTRY                  
 MODE AMODE(31)                  
 MODE RMODE(24)                  
 NAME CFTMAIN(R)                

 INCLUDE SYSLMOD(CFTCOPL)        
 ENTRY CFTENTRY                  
 MODE AMODE(31)                  
 MODE RMODE(24)                  
 NAME CFTCOPL(R)                

RC will be 4, with msg : IEW2651W 511C ESD AMODE 24 CONFLICTS WITH USER-SPECIFIED AMODE 31 ,
But the load modules should work
This bypass is just for emergency situations where the SP2+Patch cannot be straight applied.
(it works also for older CFT version where no fix will be delivered)