help me to solve below information on my message

Hi!! I am using u version 5... When i write a structure and build it, it shows that there is a error on this #include<regx52.h> so how will I solve it ?.
help me to solve below information on my message

Hi!! I am using u version 5... When i write a structure and build it, it shows that there is a error on this #include<regx52.h> so how will I solve it ?.
plz read. need help with sample programs. They wont compile.

dear friends, I downloaded sample and everything is fine. except I cannot run usb samples. there's a folder "C:\DOWNLOADS\EXAMPLES\USB-EX1" and under that folder there's a "USBMOUSE.c" file. it loads...
plz read. need help with sample programs. They wont compile.

dear friends, I downloaded sample and everything is fine. except I cannot run usb samples. there's a folder "C:\DOWNLOADS\EXAMPLES\USB-EX1" and under that folder there's a "USBMOUSE.c" file. it loads...
GETTING ERROR WHILE COMPLING MY PROGRAM LISTED BELOW

.\Objects\test1.axf: Error: L6218E: Undefined symbol stderr_putchar (referred from retarget_io.o). .\Objects\test1.axf: Error: L6218E: Undefined symbol stdin_getchar (referred from retarget_io.o). ...