FWIW, this is what I have:
EthernetIPforCLXCom1.Write("PD_AB300:AB301:HMI_AB301_F2103PT.ACtrl[0]", CSng(0.09))
EthernetIPforCLXCom1.Write("PD_AB300:AB301:AB301_F2103PT.ACtrl.LowFaultSP", CSng(0.09))
Which causes a "PLCDriverException was unhandled" fault (without a Try - Catch). With the Try - Catch, it responds with a "CIP Error Path Segment Error".
I've got the PLC address correct, and the slot number is correct as well. The PLC can be pinged with no problem, and I have it up in RSLogix at the moment.
Thanks!