Error: There was an exception running the extensions specified in the config file. ---> Maximum request length exceeded.
The files being sent are exceeding the limitations specified by SharePoint.
SharePoint Maximum Request Length Exceeded (maxrequestlength):
You will need to modify your web.config and/or system.config files to have a higher maxrequestlength property.
Here is the MS article on how to accomplish this: http://support.microsoft.com/kb/925083
We suggest setting it to something high enough to accomodate any files you may upload: maxRequestLength="102400"
1. Open IIS
2. On the Server node, select Request Filtering
3. Click on Edit Feature Settings on the right sidebar
4. In the Maximum Allowed Content Length (Bytes) textbox enter your value
5. Save Changes