G'day and welcome to the forums.
Start with removal of Rosetta as it is not compatible with Lion, as PowerPC applications will not run on Lion. Then go into System Preferences > Startup Disk and make sure the drive is selected.
the problem is that rosetta now is including in the system and i can't find itif you go to applications and then find rosetta and drag it to the trash
what version of rosetta is it?
Ty anywayi dont know about the system but i would say maybe try dragging rossetta to the trash, there maybe a rossetta uninstall but i dont know how to do that, sorry i cant help anymore.