RE: STRHOSTSVR cmd has Disappeared !

Silly enough answer, but is your user profile authorised to the STRHOSTSVR
command?
RTVCMDSRC reveals that the source for V4R5 STRHOSTSVR is:

/*           CRTCMD     CMD(*LIBL/STRHOSTSVR) +
/*                      PGM(QIWS/QZSOSEHS) +
/*                      SRCFILE(*LIBL/QCMDSRC) +
/*                      SRCMBR(STRHOSTSVR) +
/*                      THDSAFE(*NO) +
/*                      MLTTHDACN(*SYSVAL) +
/*                      TEXT('Start Host Server') +
/*                      VLDCKR(*NONE) +
/*                      MODE( +
/*                        *ALL) +
/*                      ALLOW( +
/*                        *ALL) +
/*                      ALWLMTUSR(*NO) +
/*                      MAXPOS(1) +
/*                      PMTFILE(QIWS/QIWSMSG) +
/*                      MSGF(*LIBL/QCPFMSG) +
/*                      HLPSHELF(*LIST) +
/*                      HLPPNLGRP(*LIBL/QHZSOCMD) +
/*                      HLPID(STRHOSTSVR) +
/*                      HLPSCHIDX(*NONE) +
/*                      CURLIB(*NOCHG) +
/*                      PRDLIB(QIWS) +
/*                      PMTOVRPGM(*NONE) +
/*                      AUT(*LIBCRTAUT) +
/*                      REPLACE(*YES) +
/*                      ENBGUI(*YES)

/*  Internal info
/*    PGM call state:           *SYSTEM
/*    CCSID:                    37

             CMD        PROMPT('Start Host Server')
             PARM       KWD(STRHS) +
                        TYPE(*INT4) +
                        CONSTANT(1) +
                        MIN(1)
             PARM       KWD(SERVER) +
                        TYPE(*CHAR) +
                        LEN(10) +
                        RSTD(*YES) +
                        SPCVAL( +
                          (*CENTRAL 0) +
                          (*DATABASE 6) +
                          (*DTAQ 1) +
                          (*FILE 5) +
                          (*NETPRT 2) +
                          (*RMTCMD 3) +
                          (*SIGNON 4) +
                          (*SVRMAP 7)) +
                        SNGVAL( +
                          (*ALL ALL)) +
                        MIN(1) +
                        MAX(8) +
                        EXPR(*YES) +
                        PROMPT('Server type')
             PARM       KWD(RQDPCL) +
                        TYPE(*INT4) +
                        RSTD(*YES) +
                        DFT(*ANY) +
                        SPCVAL( +
                          (*TCP 3) +
                          (*IPX 4)) +
                        SNGVAL( +
                          (*ANY 1) +
                          (*NONE 2)) +
                        MAX(2) +
                        EXPR(*YES) +
                        PROMPT('Required protocol')
  --buck