You cannot take a checkpoint if the program has a name/token pair that is not a task-level name/token that was created with the IEANT_CHECKPOINTOK value in the persist parameter. See the IEANTASM macro. You can undefine a name and redefine it after taking a checkpoint or you can add the IEANT_CHECKPOINTOK option. Ensure that the name and the token contain information that will be valid after the restart. For example virtual storage addresses in user subpools will be unchanged but the ASID (address space identifier) probably will be different. The name/token service is described in z/OS MVS Programming: Assembler Services Reference ABE-HSP.