I have been working for an hour. I have working for an hour.

第一句是没有什么问题的,完成进行时,而且动作还需要继续做下去.说明还要继续work下去
第二句没有这种说法吧,可以用现在完成时,I have worked for an hour,但是已经完成了,不需要再work了