Unbound KMC_LIBS path

Hi,

I'm trying to rebuild the project I downloaded from:

"Implementing a Metadata Extension for KMC Properties"

https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/kmc/implementing a metadata extension for kmc properties.article

but when I try to rebuild it using "Project > Rebuilt Project" I get an error on the KMC_LIBS Java path (same reason I can't create a PAR file):

Error The project was not built due to classpath errors (incomplete or involved in cycle)

Error Unbound classpath variable:'KMC_LIBS/someJAR'

...

The "ECLIPSE_HOME/someJAR" were included successfully.

Does anyone know how to set the right path to this KMC_LIBS path? I'm using Netweaver Developer Studio 2.0.9.

Thanks!