I made A hal Skni before And when i was Using it i placed the skin in the skin DIR, and the .UHP in the Ultra hal assistant folder.
The plugin installer.
The plugin installer Is just (a DAT) plugin.DAT which needs to be edited by a NotePAD. Inside the dat you specify the relevent path details.
Look inside one of the Plugin.dAT In one on the ZABAWARE plugins AND have a try..
If you cant Make the PLUGIN.DAT dont worry. as when my skin was posted IT was just zipped up...
http://www.zabaware.com/forum/topic.asp?TOPIC_ID=1351