Yea this mod is definitely broken but I was looking and there's an error with engine_stocks.inc so it's a possible AMXX bug, have a look:
Code:
L 02/05/2005 - 14:25:15: [AMXX] Native error in "entity_get_int" on line 75 (plugin "stalkermode.amxx").
L 02/05/2005 - 14:25:15: [Engine] Invalid player 4 (not in-game)
L 02/05/2005 - 14:25:15: [AMXX] Debug Trace =>
L 02/05/2005 - 14:25:15: [AMXX] [0] Line 75, File "engine_stocks.inc"
L 02/05/2005 - 14:25:15: [AMXX] [1] Line 265, File "stalkermode.sma"
Now having an AMXX include in there for a runtime error makes me wonder if it's an AMXX bug of some sort but this mod will make your server crash and it will make players get disconnected with Reliable Overflow Errors, also that error posted above will come up and make the server lock up completely after flooding the AMXX log file hundreds of times.