Internal error inside of dragonfly: Type mismatch

Hi
I tried debugging one of my html-pages with dragonfly and run into a dragonfly bug before I found mine:
I attached the output of the error console
dragonfly itself stopped execution of the page but did not tell me about the type of error.

Wolfgang

here comes the output of the error console:
------------------------------------------
JavaScript - http://localhost:3000/partner
Event thread: change
Error:
name: ReferenceError
message: Statement on line 1: Undefined variable: testgruppierung
stacktrace: Line 1 of function script
testgruppierung(this)
...
JavaScript - https://dragonfly.opera.com/app/
Event thread: click
Error:
name: TypeError
message: Statement on line 3603: Type mismatch (usually non-object value supplied where object required)
stacktrace: Line 3603 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
function(container){container.clearAndRender(templates.error_log_messages(ErrorConsoleData.getDragonflyMessages()));container.scrollTop=container.scrollHeight;}
Line 562 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
{var id='',i=0,container=null;for(;id=this.container_ids;i++){container=document.getElementById(id);if(container){this.createView(container);messages.post('view-created',{id:this.id,container:container});}}}}
Line 714 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
container.className=view.container_class||'';container.innerHTML='';view.update();}}
Line 455 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
function(view_id){var view_id=this.tab&&this.tab.activeTab;if(view_id){this.toolbar.setup(view_id);this.update(this.left,this.top,true);this.container.setup(view_id);}}
Line 688 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
this.cell.setup();this._history[this._history.length]=this.activeTab;if(this._history.length>HISTORY_MAX_LENGTH){this._history.splice(0,this._history.length-HISTORY_MAX_LENGTH);}
Line 825 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
function(event,target){target=target.parentElement;var tabs=UIBase.getUIById(target.parentElement.getAttribute('ui-id'));var view_id=target.getAttribute('ref-id');if(tabs){tabs.setActiveTab(view_id);}
Line 822 of linked script https://dragonfly.opera.com/app/script/dragonfly-de.js
eventHandlers[type][handler](event,ele,container);}}
...
JavaScript
Unknown thread
Opera Dragonfly info message:
script source is missing for given id in views.js_source.showLine

Can you describe how to reproduce that error? ( ideally with a test case )