During the debug of form user face issue to find out the trace file of the activity. Below script make it easy to find trace file through concurrent request id.
SELECT 'Request id: ' || request_id,
'Trace id: ' || oracle_Process_id,
'Trace Flag: ' || req.enable_trace,
'Trace Name:'
|| dest.VALUE
|| '/'
|| LOWER (dbnm.VALUE)
|| '_ora_'
|| oracle_process_id
|| '.trc',
'Prog. Name: ' || prog.user_concurrent_program_name,
'File Name: '
|| execname.execution_file_name
|| execname.subroutine_name,
'Status : '
|| DECODE (phase_code, 'R', 'Running')
|| '-'
|| DECODE (status_code, 'R', 'Normal'),
'SID Serial: ' || ses.sid || ',' || ses.serial#,
'Module : ' || ses.module
FROM fnd_concurrent_requests req,
v$session ses,
v$process proc,
v$parameter dest,
v$parameter dbnm,
fnd_concurrent_programs_vl prog,
fnd_executables execname
WHERE req.request_id = &request_id
AND req.oracle_process_id = proc.spid(+)
AND proc.addr = ses.paddr(+)
AND dest.name = 'user_dump_dest'
AND dbnm.name = 'db_name'
AND req.concurrent_program_id = prog.concurrent_program_id
AND req.program_application_id = prog.application_id
AND prog.executable_application_id = execname.application_id
AND prog.executable_id = execname.executable_id;