Map Server crashes

[Severus]

Hello rAthena Community,

we have some big issues:

Sometimes suddenly the map server crashes.

We're getting this Error:

[info]: Closed connection from '127.0.0.1'.
[info]: Saved char 150005 - Severus: status.
[info]: Saved guild (8 - LilienRO GM Gilde): connect members
[info]: Saved char 150136 - Teraxes: status skills.
[info]: Saved guild (9 - Blacklist): level members
[Error]: map_clearflooritem_timer : error
[info]: Saved char 150056 - Cory: inventory status.
[Error]: Server received crash signal! Attempting to save all online characters!
[info]: Saved char 150005 - Severus: status.
[info]: Saved char 150056 - Cory: inventory status.
[info]: Saved char 150139 - Winternight: inventory status.
[info]: Saved char 150153 - AWESOME CHAMPION: inventory status.
[info]: Saved char 150070 - Cobbs: inventory status.
[info]: Saved char 150069 - Balmung: inventory status.
[info]: Saved char 150169 - FreeStyle-: inventory status.
[info]: Saved char 150107 - Final: status skills hotkeys.
[info]: Saved char 150111 - Bella: inventory status.
[info]: Saved char 150140 - Eden: inventory status.
[info]: Saved char 150152 - Octavius: inventory status status2 skills.
[status]: Map-server #0 has disconnected.

We have absolutely no idea how to fix it.

We're using CentOS 6 and rAthena Trunk r15686

Thanks for your help.