1. You’ve created a web application and you’re sure that credentials are right, but you’re unable to login to the site collection in that web application.

2. Search index log returns strange errors about not finding the web application or access denied.

Then the solution is in the following article:

http://support.microsoft.com/kb/896861 

This did the trick for me:

1. Start regedit
2. Open key HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlLsaMSV1_0
3. Create a new multi-string value called "BackConnectionHostNames"
4. Type web application’s host name(s) in the Value Data box.

Save and close regedit. Then using Services under Administrative tools restart the IIS Admin service

Download:
http://technet.microsoft.com/sl-si/evalcenter/ee388573(en-us).aspx

System requirements:
http://technet.microsoft.com/en-us/library/cc262485(office.14).aspx