Error: No resource found that matches the given name (at 'title' with value

I'm trying to build android, and everthing was going smooth till i added LockScreenNotifications...

It gave me the following errors:

packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:20: error: Error: No resource found that matches the given name (at 'title' with value '@string/title_general'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:24: error: Error: No resource found that matches the given name (at 'title' with value '@string/screen_security_category'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:24: error: Error: No resource found that matches the given name (at 'summary' with value '@string/screen_security_summary'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:38: error: Error: No resource found that matches the given name (at 'dialogTitle' with value '@string/lockscreen_battery_status_title'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:38: error: Error: No resource found that matches the given name (at 'title' with value '@string/lockscreen_battery_status_title'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:38: error: Error: No resource found that matches the given name (at 'entries' with value '@array/lockscreen_battery_status_entries'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:38: error: Error: No resource found that matches the given name (at 'entryValues' with value '@array/lockscreen_battery_status_values'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:47: error: Error: No resource found that matches the given name (at 'summary' with value '@string/battery_around_lockscreen_ring_summary'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:55: error: Error: No resource found that matches the given name (at 'title' with value '@string/title_shortcuts'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:65: error: Error: No resource found that matches the given name (at 'title' with value '@string/lockscreen_buttons_title'). packages/apps/Settings/res/xml/lockscreen_interface_settings.xml:65: error: Error: No resource found that matches the given name (at 'summary' with value '@string/lockscreen_buttons_summary').

When i open up the file it looks like this:

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://ift.tt/jtTJvY

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.

-->

<PreferenceCategory
    android:title="@string/title_general"
    android:key="lockscreen_general_category" >

    <PreferenceScreen
        android:key="screen_security"
        android:fragment="com.android.settings.SecuritySettings"
        android:title="@string/screen_security_category"
        android:summary="@string/screen_security_summary">                        
    </PreferenceScreen>

    <ListPreference
        android:key="lockscreen_battery_status"
        android:persistent="false"
        android:dialogTitle="@string/lockscreen_battery_status_title"
        android:title="@string/lockscreen_battery_status_title"
        android:entries="@array/lockscreen_battery_status_entries"
        android:entryValues="@array/lockscreen_battery_status_values"
        android:defaultValue="0" />

    <CheckBoxPreference
        android:key="battery_around_lockscreen_ring"
        android:title="@string/battery_around_lockscreen_ring"
          android:summary="@string/battery_around_lockscreen_ring_summary"
        android:defaultValue="true" />

</PreferenceCategory>

<PreferenceCategory
    android:title="@string/title_shortcuts"
    android:key="lockscreen_shortcuts_category" >

    <PreferenceScreen
        android:fragment="com.android.settings.mahdi.LockscreenButtons"
        android:key="lockscreen_buttons"
        android:title="@string/lockscreen_buttons_title"
        android:summary="@string/lockscreen_buttons_summary" />

</PreferenceCategory>
   </PreferenceScreen>

can somebody tell me what i did wrong?

thanks in advance...