From: Chris Cannam <cannam@al...> - 2006-12-26 19:45:55
Aside from the (sound) suggestions in other replies:
the most common basic reason for this sort of error
is that there is simply no audio output layer in use at
all because the JACK audio server is not running, and
so no plugins that process audio (including synths)
can be loaded. In this state Rosegarden can send
MIDI to other applications or hardware, but cannot
play it as audio.
Do you have JACK running?