I can't confirm, but I read somewhere that you don't get skill-ups by direct-dueling another player. You do get skills, however, by attacking the other player's pet.
I tried a specific DB mob listed in a forum once, and didn't get a single skill up after 30 minutes. Try reading EQUnderground on this site in the EQ1 guides section. there is a tip in there about skilling up. Getting fast skill ups is a constant nerf-battle with SOE...