IMPORTANT, UPDATED SINCE HORDES OF THE UNDERDARK:
(important even if you don't have Hordes installed)

BioWare has implemented a new default way of handling the (now 5) module item-related events: OnActivateItem, OnAcquireItem, OnUnaqcuireItem, OnPlayerEquipItem and OnPlayerUnEquipItem. I am not too thrilled about this, for a number of reasons: mainly, as of patch 1.61, it doesn't work the same way whether or not you have Hordes installed. Furthermore, at least if you have hordes installed, in can break a lot for you. It's a good system if you know what you're doing, but it's not so great if you're not too confident about what's going on. Thus, to guarantee that you won't get any problems from a mixture of BioWare's system and the system I recommend that you use, I recommend that you do the following:
Remove the x2_mod_WHATEVER reference from all of the five events mentioned above, listed under the module's properties; and continue using the system described in the manual (which hasn't changed).