I have a Classic ASP application running on IIS 7. Recently run into issue uploading large files. Got that solve. But run into the error “Unable to open this Internet Site. The requested site is either unavailable or cannot be found. Please try again later.” when trying to download the uploaded document. The error message is somewhat misleading and Google search did not provide an accurate solution to the problem. Some site suggested disabling suspected add-on, uninstalling and reinstalling browser, modifying registry, disabling firewall, etc…
According to Microsoft Support site, this problem occurs because IIS enforces a default Active Server Pages (ASP) response buffer value of 4 MB when ASP response buffering is disabled. (http://support.microsoft.com/kb/944886). One of the solutions is to increase the Response Buffering Limit value. If you happen to come across this sort of problem, try look into the IIS setting. I hope someone will find this post useful.