Reinstalling uninstalled plugin

[Skiedragon]

Plugin came with no installer, just a .dll file.
I put it into plugins.
It worked well.
At some point I accidentally clicked the 'uninstall' button from Winamp's input plugins section, which uninstalled the plugin.
The .dll is still there in the plugins directory but it won't show up on the plugins list anymore. I can't figure out how to reinstall it. Where's the information hidden that winamp now rejects this dll?

I've tried everything from reinstalling winamp to eating three gallons of kryptonite, but I can't get the plugin to show up anymore.