someone can tell me how to boot Ubuntu 12.10 from Grub, I tried a lot but still getting error message
Cannot mount (hdx,msdosx)/ubuntu.iso.
You must replace hdx with the partition that contain the file. Eg: hd0 if the file is in the first partition. Replace x with 0,1,2,3 to match the partition that contain the iso file
And for msdosx, replace it with msdos1, it should work.
Last, you must copy the iso to the root of the device and rename it to ubuntu.iso