I'm not sure if it is too late to reply to this old thread.
Just to share, when i started using Quotecenter sometime last year. There were often times when i couldn't connect to the Quotecenter server on the first try and had to make several login attempts. I was on a 1 mbps line and speed was definitely not an issue. Like what Jason mentioned, there were occasions when the data stream stopped several times during a trading session and i have to reconnect again.
What i have noticed is that the problem has gone away since the beginning of this year. The connection is definitely more stable now. I don't know if this is actually due to the improvement of the Quotecenter servers. Users having this problem might want to check on their firewall setting etc.