Hi Kamala,

Dave is right, because your code might be working alright but you can not see the On/Off condition of LEDs as they are many 100 times turning ON and OFF in a second. Human eye can not notice any change if it is beyond 30~50 times in a second.
You must look at that you tied your External access pin at correcto location. b'cause normally 8051 has internal code memory, and by default tends to try reading code from its internal memory. Please tie EA pin to GND.

Goodluck

Rauf