JCLCheck module CAZ1JCKM needs to be accessible. Execute command TSO ISRDDN to display current allocations, then execute command LOAD CAZ1JCKM to verify that the module is coming from the correct load library.
Compare the user's logon proc with a user who can invoke JCLCheck successfully to ensure the same level of JCLCheck is being used. Execute TSO ISRDDN, then LOAD CAZ1RLSE to view the release number.
Check that the user's PC emulation software to invoke the TSO environment is not changing the ! character.
Check that the ISPF command delimiter has not been changed to "!'. This can be found in the ISPF option 0 (ISPF settings) panel.