[oo_jazz_oo]

PHP Code:

function onPlayerchats()
{
  if (player.chat == "/open account")
  {
    if (player.weapons.index(findweapon("-Bank/Account")) > 0) 
    {
      say2("You already have a bank account");
    }
    else
    {
      say2("You have opened a bank account!");
      player.addWeapon("-Bank/Account");
    }
} 


You should use php tags for your code, and styling the code makes it easier to read.

And you were also missing an opening bracket in your else statement.