I recently started using premiere cs6 & found that if i import layerd photoshop file as a sequence save it & close the application. File does not reopen. i searched sevrel forum but did not found any satifactory solution.
I did dicovered a workaround. check steps below:
1. Import photoshop file as sequence
2. open sequence with all the layers-> Copy all the layers
3. Make a new sequence & choose appropriate preset ie resoluton & codec of project
4. paste all the layers in new sequence.
5. MAKE SURE you delete photoshop sequence that was made when importing .psd
It will work---
I have made a video if you dont understand the steps
Premeire CS6 & photoshop "codec not found" bug fix