Ubuntu :: Can't Format SD Card?

I've tried everything--from the CLI to GParted and back--but I can't seem to format my SD card. I know it's not the card because it is recognized in three other devices, which offer to format it because they don't think it's formatted.When in GParted, I can create a new partition table and create a new partition, but after that completes, the card remains grey and the GParted tells me the disk label is unrecognizable.When I go at it with fdisk/mkfs.vfat, I'm told:

Code:

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building a new DOS disklabel with disk identifier 0x24edb58b.
Changes will remain in memory only, until you decide to write them.

After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)[code].........