Troubles while mounting ext2 from 5.1-RELEASE

Hello,

  after digging the various mailing-lists, release notes, errata and Google, I thought
I might get some help here. I have just installed a FreeBSD 5.1-RELEASE on my x86
laptop. Everything works like a charm, including DRI, except mounting ext2 :

# mount -t ext2fs /dev/ad0s2 /mnt/linux
ext2fs: /dev/ad0s2: No such file or directory
# ll /dev/ad0s2
crw-r-----  1 root  operator    4,  12 Aug  6 17:14 /dev/ad0s2
# ll -d /mnt/linux
drwxr-xr-x  2 root  wheel  512 Aug  5 17:16 /mnt/linux
# fdisk /dev/ad0
[...]
The data for partition 2 is:
sysid 131 (0x83),(Linux native)
    start 996030, size 46877670 (22889 Meg), flag 0
        beg: cyl 988/ head 2/ sector 1;
        end: cyl 1023/ head 11/ sector 63

dmesg and /var/log/messages are mute. I've found this kind of report in the recent
archives but it was never answered. How could I interpret this error message ?

Other information : the ext2 partition was formated with mke2fs by a Debian 3.0
(Woody) installer running Linux 2.2.20. Here is some output from dumpe2fs under Linux
:

$ dumpe2fs /dev/hda2
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          <none>
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      filetype sparse_super
Default mount options:    (none)
Filesystem state:         not clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              2932736
Block count:              5859708
Reserved block count:     292985
Free blocks:              5364944
Free inodes:              2847765
First block:              0
Block size:               4096
Fragment size:            4096
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Last mount time:          Wed Aug  6 16:53:27 2003
Last write time:          Wed Aug  6 17:01:48 2003
Mount count:              13
Maximum mount count:      25
Last checked:             Sun Aug  3 20:24:37 2003
Check interval:           15552000 (6 months)
Next check after:         Fri Jan 30 19:24:37 2004
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
[...]

Thanks for any hint,

Vincent.