Jay Collier on ""Are you sure you want to do this?" for all plugin updates"

I can update themes. However, when trying to update any plugin, I receive this error: "Are you sure you want to do this?"

To trouble shoot, I changed the file name for every plugin, one-by-one, and tried updating plugins ... but I've continued to receive this error. I also tried deactivating my active theme. No change.

I have not yet upgraded to 3.6; I'm with 3.5.2 in network configuration.

I am looking for suggestions.