What you are trying to do wont work because as stated above the HTTP protocol is stateless. But what is actually you problem is this particular case is that most browsers will timeout eventually, and that is usually before the user makes up their mind about what to do.
Therefore you need to have your state information embedded in the next request (this gives a lot of problems securitywise, but that is a whole other matter). And this also means that you have to cut up your processing into two segments, one where the user gives you the data and one where she/he verifies it.