I'm not sure as I have not read all the documentation, but I think there might be a bug. I set the follow (for testing):

 

<add key="CuteWebUI.AjaxUploader.GlobalMaxSizeKB" value="3000000"/>

 

 

I then tried uploading a 8KB file and the alert said 8KB exceeds the 2.something GB limit. I set it back to my normal 300KB and it works without issue. Not sure what's wrong..