in the past couple of weeks, many of you have not seen an "Edit" button, for your existing plugins or scripts, despite having the correct permissions. I have now traced the problem and, hopefully, fixed it. I have tested a couple of plugins by users I've had contact with regarding this problem and they work for them, but I couldn't test all content. Therefore, please check and if something's wrong, please let me know!
Also, let me take this moment to apologize to all of you for taking so long to fix this! I know it greatly inconvenienced you.
This was a really thorny problem, because on the surface everything looked right. Finally, I had to dig into the internals of our CMS to figure it out. Unfortunately, I'm also quite busy at work right now, so it took a while until I could take some time out for this.
btw, I'd also like to thank the developers of the Firebug firefox plugin, and the Drupal support module for Firebug. I can safely say that without these tools, which allow me to look at all SQL queries performed during page load, I wouldn't have figured out where the problem was (or at least it would have taken much longer).