Make sure both of these files are present:
DrumsUI/Settings/DrumsUI_AddPoi_C2C.xml
DrumsUI/Settings/DrumsUI_AddPoi_ItemNotes.xml
As well as these 2 files in your main custom Ui folder:
eq2ui_popup_add_poi.xml
eq2map_ignorelist.xml
Also, you have 4 lines that are incorrect in your eq2ui_custom.xml:
<include>DrumsUI/DrumsUI_StatBarWindow.xml</include>
<include>DrumsUI/DrumsUI_EffectsWindow.xml</include>
They should look like this:
<include>DrumsUI/Settings/DrumsUI_StatBarWindow.xml</include>
<include>DrumsUI/Settings/DrumsUI_StatBarSettings.xml</include>
And the other 2 lines:
<include>DrumsUI/DrumsUI_browser_favorites.xml</include>
<include>eq2ui_mainhud_startbutton.xml</include>
You don't need these included. The favorites are automatically included in the browser xml file, and mainhud_starbutton should definitely not be included here.
They wouldn't be affecting your problem though.