I continue having this problem. The 'workaround' isn't really one in my eyes as it requires you to own at least two Macs and being able to establish a FW800 connection.
I have a iomega 1TB external drive with USB only; that's the drive I'm experiencing the issue with. I haven't done anything unusual with it; I used it to make a TimeMachine Backup with it in Snow Leopard and then to restore my Lion system with said backup, everything worked fine even when I started using TimeMachine with it in Lion.
TimeMachine eventually complained and the disk couldn't be read anymore, which caused me to erase and partition it, using GPT with MacJournaled (HFS+) for the main partition (I was planning to use for my TimeMachine volume) and NTFS (I'm using Paragon since Lion cancelled 3G and MacFuse, thanks to Apple for that btw) for another partition I planned to use for music etc.. Once again after a week of successful work with this configuration, the NTFS partition couldn't be read anymore and can't to this day while the TimeMachine volume shows, but can't be accessed.
As you can probably read between the lines, I'm not very happy with this situation. I never experienced any problems concerning file systems in Snow Leopard and I'm a little disappointed this has changed and even more disappointed it hasn't been fixed yet. Just as a sidenote in case anyone at Apple actually reads this.
If anyone has any clue on how to get rid of the "Unable to write to the last block of the device" message, no matter how, and reformat the ******* thing, I'd be quite thankful.
Before you ask - safely erase didn't work, although this was indicated by a similar thread somewhere, I'm not sure where anymore. It doesn't say "Unable to write to last block" but it still fails to erase.