ragul, the Messages and Codes
manual gives you the user response for an AEXZ abend:
Use the transaction dump to determine the cause of the failure. For further assistance, or if module DFHDUIO is not loaded and no transaction dump is available, contact your system programmer.
In other words, you either need to go through the transaction dump to find out what caused the problem, or if that is beyond your skill set (likely it is) you need to contact your site support group and get your CICS system programmer to look at the transaction dump for you, or to otherwise help you resolve your issue. Asking questions on a forum is, essentially, of no use at all since we do not work at your site and do not have access to your transaction dump, hence have no way to debug the issue.