When the user tried to start debugging of CDC projects (using Debug menu item), debugger is not attached. When the emulator stopped the log contains following error:

C:\Users\Alex\Documents\NetBeansProjects\CdcApplication1\nbproject\build-impl.
xml:1157: Failed to parse "${debug.delay}"
BUILD FAILED (total time: 22 seconds).

The problem is reside in the corresponding Ant task:

<target name="-cdc-hi-debug" if="cdc-hi-platform.trigger">
        <taskdef name="freePortRetriever" classname="org.netbeans.modules.j2me.cdc.project.savaje.FreePortRetriever" classpath="${libs.savaje-ant-utils.classpath}"/>
        <freePortRetriever debuggerPortProperty="active.debug.port"/>
        <parallel>
            <exec executable="${platform.home}/bin/emulator">
                <arg value="-cp"/>
                <arg value="${basedir}/${dist.dir}/${dist.jar}"/>
                <arg value="-Xdevice:${platform.device}"/>
                <arg value="-Xmain:${main.class}"/>
                <arg value="-Xrunjdwp:transport=dt_socket,address=${active.debug.port},server=y,suspend=y"/>
                <arg value="-Xdebug"/>
            </exec>
            <property name="debug.delay" value="5000"/>
            <nb-mobility-debug address="${active.debug.port}" name="${app.codename}" delay="${debug.delay}" timeout="${debug.timeout}" period="2000"/>
        </parallel>
    </target>

Following lines are executed in parallel:

<property name="debug.delay" value="5000"/>
<nb-mobility-debug address="${active.debug.port}" name="${app.codename}" delay="${debug.delay}" timeout="${debug.timeout}" period="2000"/>

This is incorrect.

The solution is to place these two lines 
inside <sequential>...</sequential> tags.