I assume the script will be only executed for player characters, so I would suggest disabling check for creature items in your script (those can't be equipped/unequipped by players).
I think this is complete list of PRC items for 3.5 beta 2:
Items that can be equipped by players
base_prc_skin
Natural Weapons:
PRC_UNARMED_SP
PRC_UNARMED_S
PRC_UNARMED_B
prc_shftr_gore_*
prc_rdd_bite_*
prc_claw_1d6l_*
Shifter PnP class:
shifterhide
pnp_shft_cweap
epicshifterpower
Lich class:
lichamulet
soul_gem
Whip Of Shar spell:
whipofshar
Pyrokineticist class:
prc_pyro_lash_wh
Magic Stone spell:
magicstone
Crown of Might/Protection spell:
prc_crown_prot
prc_crown_might
Soulknife class:
prc_sk_mblade_ss
prc_sk_mblade_ls
prc_sk_mblade_bs
prc_sk_mblade_th
psi_sk_tshield_0
Vassal of Bahamut class:
Platinumarmor4
Platinumarmor6
Platinumarmor8
Warlock class:
prc_eldrtch_glv
Bone Blade spell:
wswgs071
wswgs072
wswgs073
wswls091
wswls092
wswls093
wswss071
wswss072
wswss073
Warforged race:
prc_wf_woodbody
prc_wf_helmwood
prc_wf_mithbody
prc_wf_helmmith
prc_wf_admtbody
prc_wf_helmadmt
prc_wf_unacbody
prc_wf_helmhead
prc_wf_compbody
Arrow of Bone spell:
PRC_AB_ARROW001
PRC_AB_BOLT
PRC_AB_BULLET
PRC_AB_DART
PRC_AB_THRAXE
PRC_AB_SHURIKEN
Serpent Arrow spell:
prc_serparrow
prc_serpbolt
prc_serpdart
Samurai class:
codi_mw_katana
codi_mw_short
===========================================================================
Other items
Gem Cage spell:
it_gemcage_gem
Dweomer Thief spell:
it_dweomerthief
Liquid Pain spell:
prc_agony
Energize Potion spell:
prc_it_enrgpot
Convert Wand spell:
prc_cwand_cmw
prc_cwand_clw
prc_cwand_cmdw
prc_cwand_csw
prc_cwand_ccw
Master Harper class:
mh_it_harp
mh_it_luth
mh_it_flute
mh_it_cor
PRC Poison system:
prc_it_poist0
prc_it_poist1
prc_it_poist2
prc_it_poist3
Supply Based Rest system:
supplykit001
supplykit002