as mr sankar had asked that the file he downloaded from elektor web site is properly fitting in at89c2051,yes because they uses full licenced version of the compiler,but mr sankar is using evaluation version which can only compile the code under 2K limit and that too starts at addres above 2k,that means you will have to use some device having 4k of flash memory,while you programa in assembly you use ORG 0000 like directive to tell the assembler that your code starts from this location(reset vector of 8051)but when you are using keil evaluation version then the compiler inserts a long jump instruction at reset vector(that is 0000)this long jump points to some memory location above 2k address space.Hope this helps mr sankar,just a very basic explanantion.

SAIF ULLAH KHALID.