System.Net.WebException The operation has timed out

hi,
I am trying to make an httpwebrequest to a simple .aspx page which performs some operations on the database and store the results in a file. When i try to read the response using a
StreamReader it gives this error "System.Net.WebException The operation has timed out"

In the web.config the values for httpRuntime are as follows:

<httpRuntime maxRequestLength="1948576" executionTimeout="13600" />

What could be the reason?
...