I am sending an updated copy of the CSSMenuWriter\cssmw_home\treexml.xml file to fix the error you are getting, please copy it to CSSMenuWriter\cssmw_home\ folder in your power store site.
After editing the menu, you may need to change line 2 and 3 back to:
$WA_localRoot = "" .$WAGLOBAL_localRoot ."";
$WA_remoteRoot = "" .$WAGLOBAL_remoteRoot. "";