1-No action found for boot device,
means your system is not getting PXE and you WDS service is not running on server, though you have configured all task sequence.
just restart WDS services and reconfigure your PXE,
2-The computer associations are not created by the import computer information wizard in SCCM 2007 Service pack 2
You click the following item in the Configuration Manager console:
Computer Management\Operating System Deployment\Computer Association
-->You run the Import Computer information Wizard to import new computer information.In this scenario, the computer associations are not created when the new computer information is imported. Therefore, there is no new node in the computer association list.
that mean you server is not updated with the kb989270 patch, so you must have to install hotfix for more information see http://support.microsoft.com/kb/980270 which should fix the problems with objects in the collections