I've just tested your case with the following parameters:
IEQUI-EQUNR (Equipment number)
IEQUI-EQTYP (Equipment category)
IEQUI-MATNR (Material number)
IEQUI-SERNR (Serial number)
IEQUI-S_EQUI = 'X'
IEQUI-LBBSA (Stock type, such as '01' for unrestricted use)
IEQUI-B_WERKS (Plant such as '1000')
IEQUI-DBKNZ = 'X'
IEQUI-EQUPD = 'X'
It's working fine and the Equipment has been activated. As said before everytime I use fm BAPI_TRANSACTION_COMMIT in sequence with this fm i.e., SERIALNUMBER_LIST_UPDATE.
Good luck
KJogeswaraRao