you have the syntax slightly wrong:
$RecipArray[$RecipIndex][0]["[trader_first_name]"]
should be:
$RecipArray[$RecipIndex][0]["trader_first_name"]
the square brackets are not needed inside of the quotes.
Ray wad used them in his example as a way of denoting a variable. So:
[yourColumnName]
should be replaced with your column name:
trader_first_name