I am getting a similar error as Clod in Forum Thread ID: 120168 when using the ProgressBarAdv from version 22.214.171.124 Target: 4.5.1. Visual Studio 2015 Community Edition.
The designer cannot process the code at line 33, please see the Task List for details. The code within the method 'InitializeComponent' is generated by the designer and should not be manually modified. Please remove any changes and try opening the designer again.
Adding the control and running the program in debug works just fine, until I save the changes made and reopen the designer. Then it shows up every time the designer for the form containing the control is opened.
I saw that you were able to reproduce the error in a reply to Clod, is there a resolution or work around for this error at this time?