uidesigner/com.nokia.sdt.series60.componentlibrary/components/menu/SystemMenuItem.properties
Remove ISymbianSDK#getPrefixFile. You can get this from ISDKBuildInfo#getPrefixFromVariantCfg().
friendlyName=System Menu Item
information=A system menu item, which cannot be edited.
text=text
textDescription=Canonical menu item text
command=command id
systemMenuItemContainmentErr=This is a System Menu Item and cannot be modified.