plugin ecommerce install problems

I uploaded the wp-ecommerce plugin to the plugin folder. It failed to load properly and the errors showed up on the front page of the site. Should I have uploaded the zip in the root of the site instead of into the plugin folder? If so, then wouldn’t that conflict with the wordpress install?

My apologies for any duplication of this message, but it did not seem to be appearing so I put it in again. Thanks for your help.