Hook in classes from com.android.internal.telephony.*

Hi guys, i'm having a problem and maybe someone can help me.
Everytime i try to hook in classes from the package com.android.internal.telephony.* i get NoClassDefFoundError . I am trying to hook on the method addOrUpdate from com.android.internal.telephony.util.BlacklistUtils class.

The class is inside framework/opt/telephony/src/java/com/android/internal/telephony/util/BlacklistUtils.java in cyanogen sources.


I'm still learning how to make xposed modules, and every thing work great , except on classes from the package com.android.internal.telephony.*