Hi Chris,
It sounds like something might be causing a JavaScript error on the Widgets screen. I haven’t had any other reports of Simple Page Sidebars causing issues, so we need to figure out if it’s actually the cause of the issue.
The first thing you should do is deactivate all of your plugins except Simple Page Sidebars. Then visit the Widgets screen and see if you can manage your widgets. If so, it’s likely one of the other plugins you have activated.
Here’s a handy flowchart that outlines the basic steps for pinpointing the cause of conflicts: http://scribu.net/files/plugin-troubleshooting-flowchart.png
Let me know what you find out.
Thanks,
Brady
Thanks very much, yes a naughty Plug in was randomly causing this issue and is now fixed!