That's the reason. For some issues there is a work around. Check their wiki. sign me a former DH customer.
Colbyt is correct,dreamhost is recently made some script not running properly on their server.Try your script in another host.
It seems most hosts are starting to dissallow URL file access and I can see why http://wiki.dreamhost.com/Allow_url_fopen
it has to do with local scripts too silly.....it won't let you use a URL to your own file...you have to use a path.
I know what allow_url disabled means, just don't get it why you need to load remote scripts? why can't you included it locally?