flash drive misery: FAT unable to read boot sector

[harmodio]

Hi there. I had a sad afternoon trying to set up my flash drive. I have FC2 kernel 2.6.5-1.358 on an dell optiplex 270X. It recognizes when I put the stick on, but then it says that its impossible to read the boot sector. When I try to mount it I get a "can't read superblock" error. I tried to format it with fdisk but I got the same answer. I formatted it under windows (FAT32) but nothing changed. Here you have the fstab and the var_log. Thanks in advance.

FSTAB:
/dev/hda7 swap swap defaults 0 0
/dev/cdrom /mnt/cdrom udf,iso9660 noauto,owner,kudzu,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,owner,kudzu 0 0
/dev/sda1 /mnt/usb vfat defaults,noauto,users,sync 0 0

VAR_LOG
Oct 21 18:55:47 AGUACATE kernel: usb 1-4.3: new high speed USB device using address 6
Oct 21 18:55:48 AGUACATE kernel: scsi5 : SCSI emulation for USB Mass Storage devices
Oct 21 18:55:48 AGUACATE kernel: Vendor: USB Model: Flash Drive Rev: 1.12
Oct 21 18:55:48 AGUACATE kernel: Type: Direct-Access ANSI SCSI revision: 02
Oct 21 18:55:48 AGUACATE kernel: SCSI device sda: 507901 512-byte hdwr sectors (260 MB)
Oct 21 18:55:48 AGUACATE kernel: sda: assuming Write Enabled
Oct 21 18:55:48 AGUACATE kernel: sda: assuming drive cache: write through
Oct 21 18:55:48 AGUACATE kernel: sda: sda1 sda2 sda3 sda4
Oct 21 18:55:48 AGUACATE kernel: Attached scsi removable disk sda at scsi5, channel 0, id 0, lun 0
Oct 21 18:55:49 AGUACATE scsi.agent[4218]: disk at /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4.3/1-4.3:1.0/host5/5:0:0:0
Oct 21 18:56:00 AGUACATE kernel: FAT: unable to read boot sector