Functional indexes

when I try to create the following index I get

CREATE INDEX TEST.fn_idx_date_to_epoch
ON bob.test1 (TRADETIME, TRADEDATE, surv_epoch.date_to_epoch(tradedate,tradetime)))
TABLESPACE DATA

i get an ORA-02158: invalid CREATE INDEX option

Any ideas?

You seem to have too many ) in that statement

Regards