I'll echo the OP in this thread. I was pretty new to WordPress when I tried to get this plugin installed and working properly. Three months later, I have learned a lot, my online shop is still not working properly and I've seen this constant angry banter online about how crappy this plugin is.
WP eCommerce is: (1) FREE and (2) OPEN SOURCE.
It is obviously a work in progress, by developers who are taxed with their jobs that actually pay their bills. There is one guy, in Texas, who has become the source for all things having to do with the plugin.
Other than that, you're on your own when you have a technical problem specific to your site. The plugin is not robust enough to deal with all the crazy configurations out there (yet). I guess it would have been nice to ave known that this was more like "beta" code, rather than a proper WP plugin.
I have a feeling that in a few months, the plugin will be better than before. I know I am going to get working trying to learn php and javascript in order to fix the problems with my WP eCommerce install. I'll be sure to post my fixes online and share them with everyone using this plugin. It's all we can collectively do to make things get better, que no?