2 of us had custom elf (both male) characters, 1 had a custom dwarf (male), and 1 was Lohse. It happened back-to-back with this configuration.
I changed from a custom elf to Ifan, and then we were able to get all 4 characters created.
I theorized it might be having 2 of the same-race of customized character that caused it, as it was one of the elves both times that didn't make it into the game and the time we removed the duplicate custom race we stopped having the problem.
