Follow these steps to resolve first error:

1. Open the project properties
2. Select Java Build Path > Libraries
3. Add a new, arbitrary library (to be deleted later) > OK
4. Wait for the workspace to refresh (or force a refresh of the project)
5. The error(s) will go away
6. Remove the dummy library

The only other references I could find were to make minor alterations of contents of the .classpath file.

To resolve the another one, do the following :

1 Edit the project's properties (right-click project, Properties, Java Build Path, Libraries, Remove and Add Library.
2 Import the project's files without the "project file".
3 Install JDK and set the path.