Bruce,
I had this problem in an earlier version of NT so I just updated to 8.17 hoping whatever file is messed up would be replaced. Unfortunately, the error it's still there.
I have not touched any of the .js files. I think the error is related to my menu because it fires everytime I open a new page.
TypeError: $.browser is undefined
var lameIE = $.browser.msie && $.browser.version < 9; jquery.....js?c=1 (line 36)
TypeError: $.browser is undefined
if ($.browser.msie) { netweb.js?c=1 (line 683)