jinja2.exceptions.TemplateNotFound error

i use flask and i got this error when i call this url: /login Here's my login method:

@app.route('/login')
def login():
    if authenticateForPanel():
        return redirect(url_for("panel"))
    else:
        getParam = request.args.getlist('redirect_uri')
        if getParam:
            ref =getParam[0]
        else:
            ref="/panel"
        return render_template( themesDir + g.blogOptions['active_theme']+'/login.html', blogOptions = g.blogOptions, ref=ref )

And the traceback:

Traceback (most recent call last):
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1701, in __call__
    return self.wsgi_app(environ, start_response)
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1689, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1687, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1360, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1358, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/app.py", line 1344, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/ozcan/Documents/python/app.py", line 209, in login
    return render_template( themesDir + g.blogOptions['active_theme']+'/login.html', blogOptions = g.blogOptions, ref=ref )
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/flask/templating.py", line 124, in render_template
    return _render(ctx.app.jinja_env.get_or_select_template(template_name_or_list),
  File "/Users/ozcan/Library/Python/2.7/lib/python/site-packages/jinja2/