You can refer to Metalink note ID 357597.1
1. Set profile “FND: Diagnostics” to “Yes” at user level.
2. Login to Personal Home Page as that user and select the “Diagnostics” icon at the top of the page.
3. Select “Set Trace Level” and click Go
4. Select the desired trace level and click Save
5. Write down the trace id number(s).
6. Perform the activity that you want to trace
7. Return to the “Diagnostics” page.
8. Select “Set Trace Level” and click Go
9. Select “Disable Trace” and click Go.
10. Write down the trace id number(s) if different.
11. Go to user_dump_dest for your database and collect the raw trace file(s)
suffixes by the trace id number(s) you have recorded.
12. Exit Applications.
Note: you can identify the user_dump_dest directory in your environment by running the following SQL:
SQL> select name, value from v$parameter where name like ‘user%’;