AsyncFileUpload does not work in Firefox 22

I tried it on three application on two pcs and result is the same, the async file upload doesn't work in firefox 22.

http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/AsyncFileUpload/AsyncFileUpload.aspx 

After some time I get the error from ffox:

"attention: script doesn't respond

Script: http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/CombineScriptsHandler.ashx?_TSM_HiddenField_=ctl00_SampleContent_ScriptManager1_HiddenField&_TSM_CombinedScripts_=%3b%3bAjaxControlToolkit%2c+Version%3d4.1.7.123%2c+Culture%3dneutral%2c+PublicKeyToken%3d28f01b0e84b6d53e%3aen%3a608fa982-dded-4326-bfe7-b13cdd701e9a%3ade1feab2%3af9cec9bc%3ae4bd8421%3af2c8e708%3a720a52bf%3a4a2c8239:12"

It works fine in iexplorer 9 and chrome 28.

Has anyone same issue?

Thanks.