Error updating diagram

[me.signing.up@…]

Hello. My diagram is not showing up and is throwing and error every time the diagram tries to update.

This is the error message from the log:

Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.2-py2.6.egg/trac/web/main.py", line 511, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.2-py2.6.egg/trac/web/main.py", line 237, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.2-py2.6.egg/trac/admin/web_ui.py", line 116, in process_request
    path_info)
  File "/usr/local/lib/python2.6/dist-packages/TracWorkflowAdmin-0.12.0.1-py2.6.egg/tracworkflowadmin/web_ui.py", line 90, in render_admin_panel
    self._parse_request(req)
  File "/usr/local/lib/python2.6/dist-packages/TracWorkflowAdmin-0.12.0.1-py2.6.egg/tracworkflowadmin/web_ui.py", line 416, in _parse_request
    self._update_diagram(req, params) # not return
  File "/usr/local/lib/python2.6/dist-packages/TracWorkflowAdmin-0.12.0.1-py2.6.egg/tracworkflowadmin/web_ui.py", line 252, in _update_diagram
    proc = Popen([self.dot_path, '-Tpng', '-o', tmppath], stdin=PIPE)
  File "/usr/lib/python2.6/subprocess.py", line 633, in __init__
    errread, errwrite)
  File "/usr/lib/python2.6/subprocess.py", line 1139, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

I was trying to find the problem but I'm not familiar with python.

Thank you

[anonymous]

I had a problem with permissions to the htdocs directory that cleared it up for me.

[Jun Omae]

It seems that dot command is missing on your environment. The plugin needs dot command of graphviz. Please install graphviz.