Deleting the preference file in Vista fixed the problem.
Yes, I have remnants from many versions of Limewire. I haven't deleted them because it looks like new versions use some of the old info.
I have 4.18.8. (I tried v.5 for about three minutes before freaking out and going back to v.4)
No, the folder was not listed for sharing. No, the files / extensions were not checked for sharing. No, new downloads were not shared. And the files were not showing up as shared in my library...but they were still being shared.

Been using LW for years and not had problems with it. Been using Vista for 9 months and had nothing BUT problems. With everything.

THANK YOU FOR THE HELP.