please help me guys

when I type:

Nokia-N900:~# mkfs.vfat /dev/mmcblk1p1 -n sdcard
mkfs.vfat 3.0.1 (23 Nov 2008)
mkfs.vfat: /dev/mmcblk1p1 contains a mounted file system.
Nokia-N900:~# mke2fs -j -L NITDroid /dev/mmcblk1p2
mke2fs 1.41.3.maemo0 (12-Oct-2008)
Could not stat /dev/mmcblk1p2 --- No such file or directory

The device apparently does not exist; did you specify it correctly?
Nokia-N900:~#

i got every time this error!! i have just rebooted the n900 ...