DCC has never been a fast method of transferring files. It's mainly meant for things like small pictures or text files, not mp3s or movies. In fact, this board has a policy against helping people with filesharing, not that we have anything against filesharing, but rather, the fact that we don't support illegal filesharing, which is a majority of what filesharing is.
The fact that you are using Vista may be having an effect, as there have been a lot of issues between Vista and mIRC.
Perform a search for Vista and you'll be able to see some of the topics.
You've already done everything that I'm aware of to be tried, while keeping with the DCC protocol.
Sorry I wasn't able to be of much (if any) help.
