Also there is a missing table after update to 1.6  

Message: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'xxxxxx_xxxxxx.ow_profileprogressbar_activity_log' doesn't exist
so i will see what i can do to fix mine and share it here with you all. 

if your table does not exist you can run this sql right from your phpmyadmin area.. 
BE SURE TO REPLACE THE ow_ WITH YOUR PREFIX if you use a dif one, MOST OF US HAVE ow as the prefix so in that case it the first two lines here would look like this 

DROP TABLE IF EXISTS  `ow_profileprogressbar_activity_log`;

CREATE TABLE `ow_profileprogressbar_activity_log` (  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,  `userId` int(10) unsigned NOT NULL,  `entityType` enum("blog-post", "event", "forum-topic", "friend_add", "group", "link", "photo_comments", "video_comments", "user_gift") NOT NULL,  `timeStamp` int(10) unsigned NOT NULL,  `entityId` int(10) unsigned NOT NULL,  PRIMARY KEY (`id`),  KEY `indexAll` (`userId`,`entityType`,`timeStamp`, `entityId`)) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

Hello

I have this table also inserted and get the following error message in the admin processing in plugin:
Message: get_object_vars() expects parameter 1 to be object, null given
File: /home/MYWEBSITE/public_html/ow_plugins/profile_progressbar/controllers/admin.php
Line: 94
It also lack the language strings in admin in the plugin settings

Best regards