Test files are 500kb - 2MB.

 

Here is an example of an error on Mozilla FireFox or Google Chrome:

 

You are probably hitting the file upload limit of IIS7.By default in IIS 7 requestFiltering  has the MaxAllowedContentLength property enabled.It specifies, in bytes, the maximum length of the content in a request. The default is 30MB.

 

 

 

 

There must be some other reason for the error, but it is not apparent other than an SSL issue or the control needs direct access to the uploaded file via the web.