I have a similar issue when i try to upload multiple files from ie8 to iis7

I'm using the last CuteWebUI.AjaxUploader.dll

 

 

Randomly the upload freeze

 

 

and after some minutes i receive this error:

 

 

How can i fix this problem?

 

I have found a workaroud from microsoft:

 

 

I have tested on my client and it works, but i can not modify all the external contributors clients