Jet Flash filesystem is forced as readonly

[Per Anton Rønning]

System log messages:
*** snip ***
Oct 27 11:36:13 localhost kernel: usb 1-2: New USB device strings: 
Mfr=1, Product=2, SerialNumber=3
Oct 27 11:36:13 localhost kernel: usb 1-2: Product: Mass Storage Device
Oct 27 11:36:13 localhost kernel: usb 1-2: Manufacturer: JetFlash
Oct 27 11:36:13 localhost kernel: usb 1-2: SerialNumber: TCC95547
Oct 27 11:36:18 localhost kernel: scsi 9:0:0:0: Direct-Access     
JetFlash TS4GJF185        8.07 PQ: 0 ANSI: 2
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] 7987198 512-byte 
hardware sectors (4089 MB)
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] Write Protect is off
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] Assuming drive 
cache: write through
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] 7987198 512-byte 
hardware sectors (4089 MB)
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] Write Protect is off
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] Assuming drive 
cache: write through
Oct 27 11:36:18 localhost kernel: sdb: sdb1
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: [sdb] Attached SCSI 
removable disk
Oct 27 11:36:18 localhost kernel: sd 9:0:0:0: Attached scsi generic sg2 
type 0
Oct 27 11:36:19 localhost hald: mounted /dev/sdb1 on behalf of uid 500
Oct 27 11:36:19 localhost gnome-keyring-daemon[2713]: adding removable 
location: volume_uuid_7A22_FF86 at /media/disk
Oct 27 11:36:30 localhost kernel: FAT: Filesystem panic (dev sdb1)
Oct 27 11:36:30 localhost kernel:    fat_free_clusters: deleting FAT 
entry beyond EOF
Oct 27 11:36:30 localhost kernel:    File system has been set read-only
*** end snip ***
This has been the  case for some days, I have been browsing the internet 
to see if someone has a solution to it.
I don't know what has brought this about, but the problem is that that I 
use the memory pen for backup purposes, and no write access is denied. I 
cannot change this even if I'm root.
I guess it may have something to do with mount options, but I have not 
yet found a way to check this i F9, or update it. This may be 
elementary, but I fail to find a way to fix it.

BRGDS
PAR