[U-Boot] Continuos reboot in u-boot 1.3.4

[Virupax.SS at Lntemsys.com]

Hi 

I am using u-boot 1.3.4 ( got from atmel) on AT91SAM9G20 , If enable the 
ethernet related code in the u-boot ( drivers etc) the board starts 
resetting again and again continuously without giving any error message. 
Please somebody tell me what type of mistakes ( coding errors ) make the 
board to reset in u-boot. Or it is because of writing some wrong values in 
the controller resisters. 
Thanks