SoCalBluetooth... the EXACT same thing happened to me. I was copying stuff from my PC to my duo, when the operation failed... instead a ton a junk folders with crazy names were created on the duo, and they could not be deleted... the psp was unable to format it, but i finally got the computer to do the job.... minutes later, my 1gig duo card was fried. it formatted okay, let me copy stuff to it, but then after using it in the psp during a doom swap attempt, it was no longer readable/detected by the psp nor the computer... and now i've got to wait up to a month to get the replacement from sandisk...
i'm definitely hoping for some alternate method in the near future, as i believe other ppl will experience memory stick failures in the coming days.
if there were a smaller mem stick->duo converter, then the memory stick select (128megsx2)option would be ideal.