Well, had the same problem,
didn't played d2/ce for a long time and reinstalled all the stuff but cant create any hc char aswell....
here u get my old account
nemesis-idabnfd
its password is : 123456
login with any char and u get permissions to create a hc char again.... dont delete the chars, so anybody can use them for this!!
regards
I hope this problem has been fixed, and that you've changed passwords.
The game sets a registry flag when you kill Baal in SC in Normal (PoC) mode. This registry flag can be set manually, and to HC you go!