Error When building ess/tra/tre and ess/tra/tre/trs DC's

I had customized the ess/tra/tre and ess/tra/tre/trs DC's and had them working, but I do not know what I did or what happened that am now getting the following errors when building, can anyone help tell what the problem could be?

Error

- The project was not built since its classpath is incomplete. Cannot find the class file for com.sap.xss.tra.model.openccmodel.OVSOpenCostcenterModel. Fix the classpath then try rebuilding this project.

- HDI_HNS15.02_D_esstra_tresap.com

Error

- This compilation unit indirectly references the missing type com.sap.xss.tra.model.openccmodel.OVSOpenCostcenterModel (typically some required class file is referencing a type outside the classpath)

- InternalVcTreReview.java

- HDI_HNS15.02_D_esstra_tresap.com/gen_wdp/packages/com/sap/xss/tra/tre/vc/review/wdp

- line 0