Sounds like an internet/ISP congestion problem. First, do some connection speed tests (do a search to find one for you). If the tests show significant differences during different parts of the day it might be time to call your provider for a solution as it may be *their* problem...

Still, my own speeds are far slower (consistently 1.3 Mbs) and I never experience hangup/stutter problems. Maybe you've got a system issue such as a resource hog, a virus, etc. Take a look at this; "10 Ways to Increase Your Internet Speed" http://www.blogtyrant.com/increase-internet-download-speed/

And perhaps using the old GT player instead of the new player and/or using low resoution (which I do) instead of high will bring about smoother lesson video play.