1. Check under Application Developer responsibility.
Make sure that you can see the custom application and table listed.

2. Is the custom application listed under System / Installations in Alert Manager?
3. Make sure APPS user can access the table from sql plus.

4. Refer to the following which is applicable for R12:

Note 216589.1 Step By Step Guide to Creating a Custom Application in Applications 11i
Note 176852.1 Integrating Custom Applications with Oracle Applications Release 11i
Note 103418.1 Beginner's Guide: Create a Custom Event Alert to Fire against a Custom Table
Note 60879.1 How To Setup Custom Oracle Alerts On Custom Applications

• Define the database events that will trigger your alert

• Specify the details for your alert

• Define actions for your alert

• Create action sets containing the actions you want your alert to perform