Sounds like the $WAGLOBAL_Root_URL variable is not set properly.
A couple of points to keep in mind when setting the $WAGLOBAL_Root_URL variable:
1) it is the address to access the index.php page included in power store.
2) it must end in a forward slash.
If the address to get your power store index.php is:
index.php
the $WAGLOBAL_Root_URL variable needs to be set as:
$WAGLOBAL_Root_URL = "http://www.mydomain.com/PowerSore/";