Network File Access|
Page 9-7 of "Using UniData" mentions:
Network File Access (NFA) — You must create the trigger subroutine and the trigger itself on the host, where the hashed file actually resides, and not on the client.
Page 3-31 of "Developing OFS/NFA Applications" lists the supported UniBasic commands. SETINDEX and READFWD are not among them.