frmcmp_batch.sh error: ORA-12514: TNS:listener does not currently know of service requested in conne

when we are compiling a customized form, it give us this error message:

$ frmcmp_batch.sh module=xxxREGIONAL.fmb userid=APPS/APPS output_file=xxxREGIONAL.fmx module_type=form batch=no compile_all=special

ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

checking the sqlnet.log file, it contains these lines:

  Tns error struct:

    ns main err code: 12564

    TNS-12564: TNS:connection refused

    ns secondary err code: 0

    nt main err code: 0

    nt secondary err code: 0

    nt OS err code: 0

but if we run sqlplus:

$sqlplus APPS/APPS

there is no issue to connect.

please help, many thanks.