I guess you had a (hopefully temporarily) glitch with your internet connection. The message "Hostname not known" indicates that the name can not be resolved to an IP address which is absolutely necessary.
Have you already tried rebooting (this includes any routing devices you use to connect to the internet) your machine?
You can test the connection (to photoshelter) from a command-line using the ping command. At a command-line window (CMD under windows, terminal for Mac), type the following command:
ping ul.photoshelter.com
If this works, and you see something like this:
PING ul.photoshelter.com (69.22.188.84): 56 data bytes
64 bytes from 69.22.188.84: icmp_seq=0 ttl=54 time=100.867 ms
64 bytes from 69.22.188.84: icmp_seq=1 ttl=54 time=100.708 ms
64 bytes from 69.22.188.84: icmp_seq=2 ttl=54 time=100.815 ms
64 bytes from 69.22.188.84: icmp_seq=3 ttl=54 time=100.661 ms
(the list is probably endless, hit CTRL-C to stop it)
You can connect to the photoshelter server. PM should then also be able to do this.
Hope this helps,
