It shouldn't be that hard to change if this is the only character issue.
Just change :

set %barmoney $calc($readini(mnycount.ini,$nick,money) - 50)

To:

set %barmoney $calc($readini(mnycount.ini,$replace($nick,$chr(91),~,$chr(93),~),money) - 50)

And :

if ($readini(mnycount.ini,$nick,money) < 50) { notice $nick You don't have enough money. TALK MORE!!! lol  |  HALT }

To :

if ($readini(mnycount.ini,$replace($nick,$chr(91),~,$chr(93),~),money) < 50) { notice $nick You don't have enough money. TALK MORE!!! lol  |  HALT }