JFFS2 as root - magic bitmask not found errors- bad superblock?

[Fuller, Vernon]

When I mount / on /dev/mtdblock2 I can mount but I get a lot of Magic
bitmask errors. Do I have a bad superblock?  Can I trust my file system?

Here is a dump, with some debug statements (VFS: ...)

Kernel command line: console=ttyS0,115200 mem=32M init=/bin/init
root=/dev/mtdblock2 rootflags=physaddr=0x240000 rootfstype=jffs2
...
Creating 4 MTD partitions on "Avocent flash":
0x00000000-0x00080000 : "Bootloader"
0x00080000-0x001e0000 : "Kernel"
0x00240000-0x006c0000 : "Filesystem"
0x00700000-0x00800000 : "PersistentStore"
...
*******
VFS: test name = </dev/root>
VFS: fs_name = <jffs2>
VFS: root name <1f:00>
*******
...
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00240020:
0x0002 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00240024:
0x2818 instead
...
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x003e0024:
0x201e instead
Further such events for this erase block will not be printed
Old JFFS2 bitmask found at 0x003f16c4
You cannot use older JFFS2 filesystems with newer kernels
JFFS2: Erase block at 0x003e0000 is not formatted. It will be erased
VFS: tried fs_name = <jffs2> err= 0
VFS: Mounted root (jffs2 filesystem) readonly.
Mounted devfs on /dev
Freeing init memory: 52K
request_irq(serial) setup_arm_irq, irq: 15
init: can't load library 'libc.so.0'
Kernel panic: Attempted to kill init!