diff -r 5b05411a81cf src/auth/auth-client-connection.c
--- a/src/auth/auth-client-connection.c	Thu Mar 15 18:24:15 2012 +0200
+++ b/src/auth/auth-client-connection.c	Fri Mar 16 22:13:36 2012 +0200
@@ -95,7 +95,16 @@
 		return FALSE;
 	}
 
-	old = auth_client_connection_lookup(pid);
+	if (conn->login_requests)
+		old = auth_client_connection_lookup(pid);
+	else {
+		/* the client is only authenticating, not logging in.
+		   the PID isn't necessary, and since we allow authentication
+		   via TCP sockets the PIDs may conflict, so ignore them. */
+		old = NULL;
+		pid = 0;
+	}
+
 	if (old != NULL) {
 		/* already exists. it's possible that it just reconnected,
 		   see if the old connection is still there. */