I had this error on one of my lines and ended up calling into Rockwell for support. The tech was extremely knowledgeable, but we weren't able to track down the problem because there were so many possible causes. I ended up finding it by eliminating objects on the screens until the problem went away, it ended up being a button addressed to an old SLC output card. The ME application didn't like that it was communicating to a CompactLogix, to an ethernet port, then a 1747-AENTR, then through a SLC backplane to a second chassis through one of those connector cables, and finally to a channel. Once I made an OTE on the CompactLogix that mirrored the state of the channel on the SLC IO (CompactLogix didn't have any issue reading it) and pointed the PanelVew BTTN at that address instead, the error went away.
And it was VERY slow when the error was happening, but the speed issues went away as well. Probably had something to do with trying to read that particular address over and over without success.
But definitely, give more info about your specific situation. If anyone can help, it's the people on this forum.