I,ve just installed Gentoo Linux 2004.1 (kernel 2.4.25) following the gentoo handbook. But when Itry to boot to linux, i get an attempt to access beyond the end of device, and after this a kernel panic....
Is it possible that my /boot partition is too small?? I create a /boot in the beginning of the disk, with 40 MB....

it would sound like your partitions are not set up correctly, and it is trying to read a point on the hard drive, as defined in the FAT, that doesn't physically exist. That'd be my interpretation of the error at least. if you boot back up using the install cd until such a point as you can access the hard drive, recheck the values entered there.

Yeah, agreed. Likely just an incorrect parameter set when you boot. One's bootloader is more powerful than one thinks, but its not completely intuitive. Before you go in and change a lot of things, if you're booting with grub, you might want to check the boot line to see if there's a parameter that you entered with a typo in your grub.conf (menu.list) file.

Why its happened to me:

-wrong "append=" (LILO) or extra params on the kernel line(GRUB)
-filesystem type which my partition was on not compiled into the kernel (reiserfs - was a module, if I remember correctly)
-using the "compact" switch with LILO on one certain drive of mine
-booting with an initrd and not pointing to it or not having "ramdisk support" in the kernel

Its likely something silly-small. Did you compile in support for your filesystem? Is your /boot partition listed properly in your /etc/fstab file? Try booting with no extra options listed in your "kernel" line of grub or "image=" like of lilo.

Ok, i double check the parameters on grub, and everything seems to be ok. I´m using initrd, and there´s a line /dev/ram0.... do I have to use always 0 or does it change? And i also have windows installed. With fdisk there´s two partitions marked as bootable partitions (one for linux and another for windows). is that correct?

Can yo post your grub config? You don't need to have both partitions bootable. I always have the one linux one I am working with (the main one if I have several distros on the drive) the bootable flag. Windows doesn't deserve such priority It can be booted without te flag. Try unflagging it.

Searching the net I found other people that are having the same problem with gentoo 2004.1. And the solution they found is to add the option ramdisk_size=8192 in the grub or lilo config file. It appears that the "regular" ram0 size isn´t good enough for gentoo!!!
I´ll give it a try........