Missing something fundamental?

Im new to using the test features in Visual Studio.
I tried some simple webtests and loadtests and it works good.

But over to my problem:

Two computers involved:
1. My computer with VS 2005 RC
2. Webserver running web application hooked to a Oracle DB.

I record a new web test:
1. I enter username / password and press login.
2. I am being transfered to a page where I can perform different tasks involving a Oracle database. I do some changes to the database.
3. I log out.

Recording everything works like a charm.
But I cannot play this web test without an error on the login page!
So everything that is recorded after the login is never done when running the test.

Details over the error:

Microsoft.VisualStudio.TestTools.WebTesting.WebTestException: Context parameter '$HIDDEN1.SetMyAction' not found in test context
at Microsoft.VisualStudio.TestTools.WebStress.WebTestInstrumentedTransaction.UpdateBindingSites(String preBoundString)
at Microsoft.VisualStudio.TestTools.WebStress.WebTestInstrumentedTransaction.PerformRequestDataBinding()
at
Microsoft.VisualStudio.TestTools.WebStress.WebTestInstrumentedTransaction.Execute(WebTestCaseContext testCaseContext, AsyncCallback completionCallback, Object callerState)

This is a code related issue.
But I cannot understand why I get the error.

Isn't a recorded web test exactly the same as "surfing" it?

[1480 byte] By [TedStrom] at [2007-12-17]