For posterity's sake: I resolved this issue. I determined there was something fundamentally screwy with the way my PC was recognizing (or not recognizing) DLL files. I ran through a few fixes from the MS support forum, and kept finding additional problems. Long story short-- it had just been too long since Ihad cleaned out my computer. There wer multiple registry problems and not a small number of malware-type programs lurking around. I finally just ended up doing a disk wipe/formatting and conducting a fresh install of Windows XP after backing up my data. After that, the clean OP install plus Pesty's enhancement pack worked just find.
Also, a quick plug for Verizon FIOS-- When configuring my router for online play, I found that Verizon has created an easy drop down menu which automatically creates the right settings with one click. Believe it or not, SFC was on the drop down list, and with one click on that option, I was set to go. Most excellent.