I am having a similar problem. I did not install the same plugin you did, but I must have done something wrong…. My whole admin panel is all messed up. I cannot use the plugin delete button, I cannot expand and collapse options panels in the interface (like the Revisions panel on posts or pages, and plugin options panels within plugin settings screens), and maybe other things I haven’t noticed.
Any suggestions would be helpful.
pz23741, as a side note, I am still able to accomplish deleting a plugin by checking it and doing it as a bulk action.