Fixed. Thanks!

I'm getting this error using newly downloaded scripts: jQuery 1.2.3 and jQuery UI 1.5.b.

Upon any attempt to move a draggable (Firebug cut/paste):

this.helper.outerWidth is not a function
[Break on this error] this.helperProportions = { width: this.helper.outerWidth(), height: this.help...

OS X 10.5.2

Firefox 2.0.0.13, Safari 3.1, Opera 9.26

Output from Opera error console (in case it's helpful):

JavaScript - http://localhost/test/d.html
Event thread: mousemove
Error:
name: TypeError
message: Statement on line 149: Type mismatch (usually a non-object value used where an object is required)
Backtrace:
  Line 149 of linked script http://localhost:8080/itruk.loads/resources/jquery/ui/ui.draggable.js
    this.helperProportions = {width : this.helper.outerWidth(), height : this.helper.outerHeight()};
  Line 130 of linked script http://localhost:8080/itruk.loads/resources/jquery/ui/ui.mouse.js
    if (this.options.start)
          Line 100 of linked script http://localhost:8080/itruk.loads/resources/jquery/ui/ui.mouse.js
    return self.drag.apply(self, arguments);
  Line 27 of linked script http://localhost:8080/itruk.loads/resources/jquery/jquery-1.2.3.min.js
    var val;
event = jQuery.event.fix(event || window.event || {});
var parts = event.type.split(".");
event.type = parts[0];
var handlers = jQuery.data(this, "events") && (jQuery.data(this, "events"))[event.type], args = Array.prototype.slice.call(arguments, 1);
args.unshift(event);
for (j in handlers)
    if (jQuery.browser.msie)
    return val;
  Line 26 of linked script http://localhost:8080/itruk.loads/resources/jquery/jquery-1.2.3.min.js
    var val;
if (typeof jQuery == "undefined" || jQuery.event.triggered)
    val = jQuery.event.handle.apply(arguments.callee.elem, arguments);
return val;
  At unknown location
    [statement source code not available]

jQuery UI 1.5b requires dimensions. Current SVN does not.