This post describes a problem we have seen several times with customers using the AIS 3GL API from within CICS. This API is commonly used to send events to an external application (e.g., to an application server using JCA or to BizTalk etc) or to activate external appications syncronously from within CICS (e.g., COM object activation).

Symptom: CICS program abends with abend code AEY9.
Reason: The AIS 3GL interface within CICS uses TCP/IP sockets to communicate with the external application. As such, this interface needs to be started within CICS.
Solution: Use the "EZAO" transaction from the CICS screen. Choose START and CICS to start the TCP/IP socket interface.

For more details on the TCP/IP socket interface under CICS, see the following IBM document:

CONTENTS "OS/390 V2R8.0 SecureWay CS IP CICS Sockets Guide" IBM Library Server