--- a/libpurple/protocols/msn/slpmsg.c Thu Aug 05 21:58:13 2010 +0000 +++ b/libpurple/protocols/msn/slpmsg.c Thu Aug 05 22:41:22 2010 +0000 @@ -245,7 +245,7 @@ slpmsg->header->session_id = header->session_id; slpmsg->size = header->total_size; slpmsg->flags = P2P_ACK; - slpmsg->ack_id = header->id; + slpmsg->header->ack_id = header->id; slpmsg->ack_sub_id = header->ack_id; slpmsg->ack_size = header->total_size; slpmsg->info = "SLP ACK";