Some basic troubleshooting things that may help would be to try and run a tracert to folding.extremeoverclocking.com and see if or where it fails.
You probably won't get all the way to their servers, but it may help at least see where you are getting stopped. (If it's real early, and switching from one ISP to another)
I got to 13 hops before I started hitting * * * * Which means that they probably have that type of traffic filtered at that point.
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\Rich>tracert folding.extremeoverclocking.com
Tracing route to folding.extremeoverclocking.com [66.98.195.24]
over a maximum of 30 hops:
3 13 ms 13 ms 12 ms 65.14.249.89
4 203 ms 204 ms 199 ms 205.152.99.137
5 14 ms 14 ms 13 ms axr00asm-1-3-1.bellsouth.net [65.83.237.2]
6 41 ms 49 ms 40 ms 65.83.236.204
7 41 ms 40 ms 40 ms peer-02-ge-3-0-1-14.chcg.twtelecom.net [66.192.2
52.108]
8 42 ms 40 ms 40 ms core-01-so-0-1-0-0.chcg.twtelecom.net [66.192.24
4.21]
9 62 ms 62 ms 62 ms dist-01-so-3-1-0-0.hsto.twtelecom.net [64.129.24
8.1]
10 62 ms 62 ms 70 ms hagg-02-ge-0-3-0-505.hsto.twtelecom.net [66.192.
246.123]
11 48 ms 48 ms 48 ms 216-54-253-2.static.twtelecom.net [216.54.253.2]
12 48 ms 48 ms 48 ms ivhou-207-218-245-28.ev1servers.net [207.218.245
.28]
13 49 ms 49 ms 49 ms ivhou-207-218-223-106.ev1servers.net [207.218.22
3.106]
14 * * * Request timed out.
15 * * * Request timed out.
16 * * * Request timed out.
17 * * * Request timed out.
It is up and running though. I just went there and checked.