After automatically upgrading a couple of times to the lastest release of the UMapper plugin (1.3.71), I'm unable to use the plugin by clicking on the U icon in my post entry. The URL for the U icon is this
window.tinyMCE.activeEditor is null or not an object. I've tested this in both IE 6 and 7 with the same results. I haven't tested it yet in Mozilla Firefox 3.0.