I know just from looking at a couple of those:
Carbonite: 3 main folders in /Addon
Auctioneer: Tons of folders in /Addons (Auc:XXXX , Enchantrix, stubby, !swatter, Informant, all into /Addons seperately)
Most of the Zip files created by Authors are designed to be unzipped with Folder Structure intact. I would say 99% of unzip utilities do this automatically, for those that don't, there should be an option. What is the name of the Unzip program you use?
*EDIT: 9 out of 10 times if you open the Zip file, and you see multiple folders.....Carbonite again for an example, 3 folders in the Zip, then those folders all have to be in the main /Addons directory. Addons like nUI, that have one main folder you can see, you just have to extract to /Addons as is, generally
