It means the Mendix jar files aren't currently on your path. The modeler should generate a .project file which contains these references if you choose the "deploy for eclipse" option in the modeler.
Alternatively, you can scout for all the jar files in your c:/Program Files/Mendix-xxx/ directory and add all of them to your classpath manually.
I did the above mentioned already, added all the libs from my c:/Program Files/Mendix-xxx/ directory. That is what I meant with all the libraries have been pointed to