Found the root cause: I was sharing the .purple configuration directory between two Ubuntu installations (symlink between homes), Feisty and Gutsy. When I recreated the Pidgin configuration from scratch in Gutsy, the crashes stopped reproducing.
In more detail, I found that the accounts.xml file from the Feisty installation (also Pidgin 2.1.0) would trigger the crash.
Found the root cause: I was sharing the .purple configuration directory between two Ubuntu installations (symlink between homes), Feisty and Gutsy. When I recreated the Pidgin configuration from scratch in Gutsy, the crashes stopped reproducing.
In more detail, I found that the accounts.xml file from the Feisty installation (also Pidgin 2.1.0) would trigger the crash.