I had a similar problem with com1 and I just skipped it and it would load the other ports fine. You could also check to see if it is running any better in cgminer 2.1.
I tried to run my lancelots with win 8 now and always get an COM3: unrecognized option error. it's the same miner and batch-file used with win 7 before. driver is installed, COM port is the wright one. any ideas?