We have noticed an issue with the post data. We found that ANTS load adds a & at the end of the post data. What this does is add a key to the Request.Params.AllKeys Collection with a key value of "null". This is breaking our code and we are not able to use ANTS load.
The post data is being added using the WebClient.HttpRequest.AddPostData Method
Fixing the code to check for null value is not an option for us at this point of time.