Vidalia doesn't recognise that Tor has started. Doesn't start polipo.
Vidalia starts normally.
Vidalia progress bar shows Tor is starting.
Progress bar halts after perhaps 1 centimetre.
Tor log shows that it has started. Tor appears as a running process.
Polipo does not start. If polipo is started manually, then Tor can be used as normal.
If Tor crashes, restart in Vidalia. Progress bar still halts after 1 cm. However Tor runs normally.