"These 2 problems have the same root cause because the first error also happens when a request is submitted with a hardcoded dynamic variable, but instead of returning an error you are just redirected to an error page."
And this problem seems like my problem.
My test webs ite also uses hidden values and my testing tool handles them.
Somehow, some vusers can not login after a load level.
Re: Hidden Value problems in web page load testing.
just because the test is not achieving it's goals doesn't mean you are doing anything wrong - I suggest the first place to look is the server resource utilization - might tell you why you're having problems