dear raj,
I was going through your post and all the reply.
Since you have got problem in interfacing RTC and Serial memory, I think you are making some mistake in I2C routines.
All I2C devices need to perform some sort of device id checking, and it may take up some processing time. And if you are making it to do this at every milliseconds, that can create problems.

My sugestion is, read the datasheet of your RTC and memory carefully (all developers care to look at the intrefacing page only).

regards
just a guest