opencart_v1.2.6 upload bug

I can't upload any image.

I using firebug to debug it.
it's show me the following code.

Permission denied to get property Window.document
[Break on this error] var response = $(myFrame.contentWindow.document.body).text();

and my userfiles and cache are 777.

BTW,my firefox 3.0.8, IE 7

what version of firefox are you using?

There is new upload script using jquery.

I might use it.

my version of firefox is 3.0.8.

where is new upload script?