I think I may have found the problem in the data creation script for populating the mp_Pages table.
If that table is empty, try this
INSERT INTO `mp_Pages` VALUES (1,-1,1,1,'Home','All Users;',0,0,'','','','',NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (2,-1,5,1,'Forums','All Users;',0,0,NULL,NULL,NULL,NULL,NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (3,-1,11,1,'Admin','Admins;',0,0,NULL,NULL,NULL,NULL,NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (4,3,9,1,'Add/Edit Pages','Admins;',0,1,'','','','',NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (5,3,11,1,'Role Administration','Admins;',0,1,'','','','',NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (6,-1,9,1,'Image Gallery','All Users;',0,0,'','','','',NULL, 0,'',0,0);
INSERT INTO `mp_Pages` VALUES (7,3,15,1,'File Manager','Admins;',0,1,'','','','',NULL,0,'',0,0);
INSERT INTO `mp_Pages` VALUES (8,3,13,1,'Feature Modules','Admins;',0,1,'','','','',NULL, 0,'',0,0);