When I compiling my code with C51 Comiler in Keil Environment I am getting
*** Error C249 Segment : Segment too large
How to solve this problem
"I compiling my code with C51"
So why did you set your toolset to 'None' ?!
For a start, Please read the manual: http://www.keil.com/support/man/docs/c51/c51_c249.htm
Then think about it: how would you ever solve any problem that's due to something being "too large"...?
For example, see the suitcase analogy in this thread: http://www.keil.com/forum/docs/thread17216.asp