Parece uma configuração incorreta de rede para miktex.org....
Tracing route to miktex.org [178.77.68.21]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms 172.28.8.2
2 20 ms <1 ms <1 ms 172.28.1.66
3 1 ms <1 ms <1 ms 172.28.1.1
4 1 ms <1 ms <1 ms a72-246-0-3.deploy.akamaitechnologies.com [72.246.0.3]
5 1 ms 2 ms <1 ms 80.67.64.193
6 2 ms 1 ms <1 ms 80.67.75.246
7 30 ms 43 ms <1 ms bst-edge-04.inet.qwest.net [63.149.66.65]
8 7 ms 6 ms 6 ms jfk-brdr-04.inet.qwest.net [67.14.5.26]
9 8 ms 6 ms 6 ms 63-235-40-58.dia.static.qwest.net [63.235.40.58]
10 82 ms 149 ms 81 ms po6.ar4.AMS2.gblx.net [67.17.107.174]
11 164 ms 103 ms 82 ms xe-1-2-0.cr-antares.ams1.hosteurope.de [206.165.75.2]
12 89 ms 208 ms 123 ms ae1.cr-sargas.lon1.he-core.de [80.237.129.186]
13 191 ms 98 ms 108 ms xe-0-1-0.cr-merak.fra2.he-core.de [80.237.129.190]
14 104 ms 343 ms * xe-0-0-0.dr-master.fal1.he-core.de [176.28.4.114]
15 317 ms 104 ms 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
16 * 104 ms * pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
17 104 ms * 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
18 103 ms * 103 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
19 104 ms * 105 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
20 104 ms * 104 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
21 104 ms * 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
22 104 ms * 104 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
23 104 ms * 103 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
24 104 ms * 104 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
25 104 ms * 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
26 104 ms * 104 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
27 104 ms * 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
28 105 ms * 104 ms pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
29 104 ms * 104 ms pvcw-5-35-228-61.dedicated.hosteurope.de [5.35.228.61]
30 104 ms * * pvcw-5-35-228-2.dedicated.hosteurope.de [5.35.228.2]
Não é possível, por exemplo, conectar-se TCP para obter uma classe Beamer usando TexWorks.
Adicionado uma hora depois
Isto é para acelerar uma solução para qualquer outra pessoa que se encontre nesta situação.
It turned out that for some reason the MikTeX 2.9 I was using could not get out to any repository. I rebuilt the db, using "mpm --update-db", and reinstalled both the MikTeX binary and the TeXworks binary. (This is on a corporate Win7 system having many security things on it. I did check firewall issues previously.) I then tried to specify the mirror to use for package downloads. In the MikTeX programs, there are is both an "admin" version and a non-admin version. You want the admin one.
If you go specify that packages are to be obtained from Internet and get the list of possibilities in place of 'pick a random one', just choose a reliable one near you.
Apply and save up the choices, and you should be in business.