The delete operation appears to be trying to load a related forum by name instead of by id:
Traceback (most recent call last):
File "/usr/lib/python2.4/site-packages/trac/web/main.py", line 451, in dispatch_request
dispatcher.dispatch(req)
File "/usr/lib/python2.4/site-packages/trac/web/main.py", line 265, in dispatch
resp = chosen_handler.process_request(req)
File "build/bdist.linux-x86_64/egg/tracforums/web_ui.py", line 295, in process_request
File "build/bdist.linux-x86_64/egg/tracforums/models/forum.py", line 234, in load
File "build/bdist.linux-x86_64/egg/tracforums/models/forum.py", line 431, in getById
File "/usr/lib/python2.4/site-packages/trac/db/util.py", line 50, in execute
return self.cursor.execute(sql_escape_percent(sql), args)
ProgrammingError: invalid input syntax for integer: "Tango HowTo"
Also shows "Delete Forums" in wiki-ized text on confirmation page.