Change General data into date format

GSM - Dec 31, 2014 at 03:18 AM

I have a date format in excel like 28/04/2014 00:00:00. I am unable to convert into date format. if i enter formula like date(A1) it is showing me error as #VALUE!.

If i try to change "3/4/2014 12:00:00 AM" this date , i am getting correct value as 4

Can anyone help me on this