I was able to record the VSTS webtest file for a particular scenario. This particular scenario takes input parameters Date Of Birth, lastname and phone number. I had stored the data in a text file and attached to the webtest file.
Now the scenario runs for first 4 records correctly but after that it fails giving the following errors
Extract Form Field '__EVENTVALIDATION' was not found
Extract Form Field '__VIEWSTATE' was not found

And i have just 10 records in the text file. But why it is passing for first 4 records and then failing for all the other records.
Can anyone please help me with this!!!!!!!