D2DBS stopped working

like 500k lines of

Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket
Jul 16 04:04:35 [error] pvpgn::d2dbs::dbs_server_loop: psock_select() failed : Socket operation on nonsocket

and "d2dbs has stopped working" in windows error.

seems to only happen with a lot of users. below 1000 concurrent users it seems fine but 1500 it can do this error and boot out all players causing rollbacks. we think it might have to do with corruption errors from unsafe strings but no idea.

Anyone with ideas?