can't login to my mac after complete restore from timemachine due to filevault

The internal HDD of my MB 13" Unibody Aluminium late 2008 was broken, so I replaced it. Then I booted from a USB stick and restored my latest TM backup to the new HDD.

When I want to log on though, after entering my password, I get an error message saying that user "johndoe" cannot log into file-vault.

I am running OSX 10.6. Please help!