[NPC] Error in buying multiples of items

[Skylinx]

[Error - Npc interface] 
 (Unknown script file)
Description: 
data/npc/lib/npcsystem/modules.lua:1151: bad argument #2 to 'error' (number expected, got string)
stack traceback:
	[C]: in function 'error'
	data/npc/lib/npcsystem/modules.lua:1151: in function 'callbackOnBuy'
	data/npc/lib/npcsystem/npchandler.lua:263: in function 'processModuleCallback'
	data/npc/lib/npcsystem/npchandler.lua:440: in function 'onBuy'
	data/npc/lib/npcsystem/modules.lua:1292: in function <data/npc/lib/npcsystem/modules.lua:1291>

This happens everytime I try to buy a multiple of a potion, rod, armor or anything.

My whole npc system is from TFS 0.3.6 [8.6]. Can someone post maybe a working lib?

Here's my modules.lua
http://codepad.org/dO8DsJ7c

 

[Limos]

You can try to use this modules.
modules.lua

 

[Nubaza]

Dont know why everyone upload things to the sh*t of speedyshare, jaja