This error is easy to reproduce using Notepad. The cause of the problem is the confusion Silk has between the literal tag - pointing at a button - and the assigned class that expects a CheckBox.
If the control appears as a Checkbox change its declaration to this:
</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">CheckBox Deactivate
tag "/[WindowsForms10.Window.8.app5]QPanel2/Deactivate"</pre><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">If the control is really a Pushbutton change its declaration to this: