I no longer see the requirement for register_globals on in the system requirements, but I have not tried to install the script on DreamHost (it is not free or open software, and I don't have a license).
If you want to use the video modules you will have to install additional software on DreamHost:
Mplayer + Mencoder
Libogg + Libvorbis
LAME MP3 Encoder
... and many find installing these to be difficult - DreamHost will not install them for you, as these are "third party" applications.
Additionally, you will have to modify your PHP installation to support:
- PHP post_max_size - 100M
- PHP max_input_time - -1
- PHP upload_max_filesize - 100M
.. again, you can do this, but it is not supported and DreamHost will not do it for you.
All that said, the phpfox "test" program available on their website reports that, at least for the basic application (no video), it should run on DreamHost. Here is a screencap of the test program run on a DreamHost shared server: