From Mike Mraz at CME:
The .ini file grammar that comes with 6.2.3 does not behave well if there is whitespace after a "]" delimiting the end of a section key.
We modified the ini.gm file to include a WS read in the "section" portion after the RIGHT_BRACKET read. Since WS is 0 or more whitespace characters, it is a harmless solution if you do not have whitespace there:
section LEFT_BRACKET WS VAL WS RIGHT_BRACKET WS $new_field $2 $save_var $TEMP \ $2 $set_as_nonleaf $save_record $2 $set_add_rule $0
The modified ini.gm grammar is attached.