MassTechnical, Inc.

If you want to upload very large files under asp.net and IIS 7.5, you need to edit settings in both web.config and the IIS Manager.
In web.config, look for the httpRuntime section, and set the maxRequestLength to the number of KBytes you want.

Now you have to open up the site in IIS. Look for the "Request Filtering icon." Double click it, and then from the Actions menu, select "Edit Feature Settings." You will see the entry for "Maximum Allowed Content." This is in Bytes, so don't use the same number you used in web.config.