[KiLLeR.]

Never seen this error and nothing found in google.

FATAL ERROR (shutting down): Z_Malloc: failed on allocation of 250 bytes

Happened to both my server. Linux, ReHLDS, AMXX 1.8.2.

[Rivotril]

what map are you using when the server crashes?

[aron9forever]

https://developer.valvesoftware.com/wiki/Z_malloc

if you have access to command line, play with the -heapsize and -zone parameters
heapsize is in kb and has max 131072, zone is in bytes and I don't know what the max or minimum is