Creating RAM disk image

I need an ext2 fs and tried to create a ramdisk image on a linux machine. I followed the commands given in the microtronix manual but get the an after typing the following commands:

# dd if=/dev/zero of=/dev/ram0 bs=1k count=1024# mke2fs -s0 -vm0 /dev/ram0 1024

Error Message: "reserved online resize blocks not supported on non-sparse filesystem"