format code appears twice.该怎么处理

format code appears twice.
EXEC SQL BEGIN DECLARE SECTION;
 varchar vs[20];
EXEC SQL END DECLARE SECTION;

EXEC SQL Insert into tbA(colDt) values(to_date(:vs, 'yyyy-mm-dd hh24:mi:ss'));
{colDT是时间类型}

为什么总是报format code appears twice?

------解决方案--------------------
你确定没把mi写成mm?