Forms authentication timing out prematurely

Hi folks.  I'm building a site in VB.NET using forms authenication as laid out in my .NET book for newbies.  Everything seems to work fine except that my session times out prematurely - the site only needs to be inactive for a minute or two before it logs me out.  I've got the timeout set to 60 minutes.  My code is as follows:

web.config
--------------
<system.web>
      <authentication mode="Forms">
            <forms name=".CookieName" loginUrl="login.aspx" defaultUrl="~/default.aspx"  protection="All" timeout="60"/>
      </authentication>
      <authorization>
            <deny users="?"/>
      </authorization>
</system.web>

Then when I process the user login, I simply do the following in the code behind on the login page:

FormsAuthentication.RedirectFromLoginPage(strUsername, False)

I've tried setting the above to "true", but it doesn't seem to make any difference.  Anyway, as I understand it, setting it to "true" simply means that the cookie persists after the browser has been closed.

Other things I've looked into:

1.  The web.config file is not being resaved by anti-virus software - I read somewhere that this often happens, but it's not happening here.
2.  I added the following to web.config under <system.web> with no real idea why it would be different to the setting above:  <sessionState mode="InProc" timeout="60" />
3.  I added a global.asax file and added something to do with timeout on application_start, but it caused a .NET error (unfortunately I can't remember the code that I used and can't seem to reproduce it now).

Does anyone have any ideas?  If you do, would you please give a detailed response as I really don't know what I'm doing.Start Free Trial