Lommy, I read "Davem" as "Davern" too for a long time (I think until I saw it typed on LJ!) so you're not alone...
I had a terrible time trying to spell Isabellkya - or Izabellkya? Isabelika? Izzabellkya? Isabellica?
and "Izzy" sounds too much like "Xyzzy" - if I'm pronouncing the latter correctly.
*sigh*
I think errors like "Fordhim" tend to become memes - other people who would
never have misspelled it on their own become confused after seeing certain well-respected downers do so enough times. Herd instinct, if you will.
Actually, I think the same phenomenon is to blame for making Macalaure female, sometime last fall, in the minds of a few downers (including yours truly).