I had this issue come up and posted on a couple different threads. I have more information now and since it looks like a jQuery issue I decided to create a new thread.
DNN 6.
When I click the Save button on the HTML module the ajax spinner just keeps spinning and I am never returned to the page. I can close the popup window or click on another page link and I can see that my data was saved. I tried Fiddler but it never gave me an indication of what was happening. Then I tried Firebug in FF and as soon as I click the Save button I get this error. I am not sure what this part of the function is doing. Hopefully it will mean much more to someone more familiar with how DNN is using jQuery.
can't convert undefined to object
/Resources/Shared/Scripts/jquery/jquery.min.js?1.6.1
Line 16
can't convert undefined to object
f()jquery...s?1.6.1 (line 16)
a = 0
b = undefined
_tabify(i=0)jquery...?1.8.13 (line 393)
_create(i="disabled", b=undefined)jquery...?1.8.13 (line 387)
widget(i="disabled", b=undefined)jquery...?1.8.13 (line 22)
f(a=Object { selected=0, fx={...}, show=function()}, c=function(), d=undefined)jquery...s?1.6.1 (line 16)
widget(g=Object { selected=0, fx={...}, show=function()})jquery...?1.8.13 (line 22)
widget(g=Object { selected=0, fx={...}, show=function()}, e=undefined)jquery...?1.8.13 (line 22)
Widget()jquery...?1.8.13 (line 20)
f(a=[div#dnnEditHtml.dnnForm], c=function(), d=undefined)jquery...s?1.6.1 (line 16)
f(a=function(), b=undefined)jquery...s?1.6.1 (line 16)
bridge(i=Object { selected=0, fx={...}, show=function()})jquery...?1.8.13 (line 20)
dnnTabs()dnn.jquery.js (line 1)
f(a=[div#dnnEditHtml.dnnForm], c=function(), d=undefined)jquery...s?1.6.1 (line 16)
f(a=function(), b=undefined)jquery...s?1.6.1 (line 16)
dnnTabs(c=Object { selected=0})dnn.jquery.js (line 1)
setupDnnEditHtml()Defaul...Up=true (line 397)
(?)()Defaul...Up=true (line 402)
createCallback(c=Object { _form=form#Form, _activeDefaultButtonClicked=false, _updatePanelIDs=[1], more...}, d=Object {
_errorHandled=false, _error=Error, _dataItems={...}, more...})Teleri...8366029 (line 6)
BeginRequestEventArgs(a=Error { message="Sys.WebForms.PageReques...',
name="Sys.WebForms.PageReques...gerParserErrorException", stack="([object Object])@http:...a9d4e%3a58366029:6\n@:0\n", more...},
d=Object { _webRequest={...}, _responseAvailable=true, _timedOut=false, more...}, f=null)Teleri...8366029 (line 15)
BeginRequestEventArgs(g=Object { _webRequest={...}, _responseAvailable=true, _timedOut=false, more...})Teleri...8366029 (line 15)
BeginRequestEventArgs(c=Object { _webRequest={...}, _responseAvailable=true, _timedOut=false, more...})Teleri...8366029 (line 15)
createCallback()Teleri...8366029 (line 6)
createCallback(c=Object { _webRequest={...}, _responseAvailable=true, _timedOut=false, more...}, d=Object {})Teleri...8366029
(line 6)
createCallback(b=Object {})Teleri...8366029 (line 6)
createCallback()Teleri...8366029 (line 6)
[Break On This Error] (function(a,b){function cy(a){return f...]&&f.event.trigger(c,d,b.handle.elem