If you right-click on SDK AlfrescoEmbedded and click Properties, then go to Java Build Path, Libraries, do you see a list of JARs? And, if so, do they look okay or do they have red X's or something on them?
I'm not sure what version of the SDK you're using, but in the early days of 3.2 Community, there was a problem with the SDK projects pointing to a bad location for the dependent JARs. You had to go to Libraries, and essentially re-add them.
If you've downloaded 3.2 Community within the last couple of weeks, I think the issue has been resolved. When you import those SDK projects, everything should build automatically with no problems.
In general I get a lot of the same kinds of eclipse errors. I'll post some more details, but it seems like maybe there needs to be a bit more details on how to get a dev environment setup in Eclipse.