Comment 1 for bug 272632

Could you try this : launch Pidgin from a terminal, then go into Tools -> Preferences -> Sound, and click on "preview" at the bottom of the window. Do you have any message like

(pidgin:9106): GStreamer-CRITICAL **:
Trying to dispose element play, but it is not in the NULL state.
You need to explicitly set elements to the NULL state before
dropping the final reference, to allow them to clean up.

(pidgin:9106): GStreamer-CRITICAL **: gst_object_unref: assertion `((GObject *) object)->ref_count > 0' failed

(pidgin:9106): GStreamer-CRITICAL **: gst_element_set_state: assertion `GST_IS_ELEMENT (element)' failed

in the terminal?

If so, it is happening with me as well, and could be a duplicate of bug #162701