This isn't really a support question from me. Someone had posted they couldn't import OPML files using the import feature.
I tried to find the post again, but failed, so I'm posting it here in the hopes he finds it.
There was the question of whether fopen() is enabled on the server. I submitted a ticket to my host and they replied:
fopen() does work with a dedicated IP for your account. You currently have a shared IP.
So it would seem that fopen() needs to be enabled to use this feature.
Hope the guy that needed this info finds it!