I installed Slideshow Gallery on the Energion Blogs site, and ran into a problem. Unfortunately I used “Network Activate” (which was not what I wanted to do), rather than just activating it for a single site.
The result apparently tries to get user privileges before the appropriate includes are loaded. The solution, however, is simple–don’t Network Activate the plugin. I doubt it’s a very useful option. After digging my way out, (by adding require_once(‘pluggable.php’); as the first line of wp-includes/capabilities.php, and then removing it after I deactivated the plugin), I simply activated the plugin only on the individual site that needed it.
(Energion.com Blog, which are a http://eneblogs.com, are available free of charge and represent a quite capable WordPress install. I’m always an e-mail away if you want a theme or plugin added, always provided the addition meets security requirements.)