Setting variables when a player enters a level

[Yen]

Alright.. I have a ladder NPC.
When the player enters the level, I want each ladder to tell the player where it is. A system handles climbing, based on this information.

When the player enters the level, it adds the ladder's ID to one array (ladders) and it adds the ladder's area to another array (ladder#).

When the player enters, the system clears the ladders, so old ladder placements aren't carried into the level.


However, the ladder ID array is randomly being erased. I'm guessing it's by the clearing of ladders when the player enters.
I tried making it set the ladder ID array after .5 seconds, but it still doesn't work.
The ladders array just randomly clears itself; if I update the level or relog, it works. However, like I said, after a while it clears itself for no reason.

Any ideas?