MT import issues

OK, I installed a brand-new fresh install of WP. I then uploaded my MT export to the server, and pointed import-mt.php at it. When I run the import, all I get back is a screen with the WP logo at the top and nothing below the black line of the logo. Even if I view the source of the page, the HTML just stops after the logo.
It’s very strange, any ideas?
FYI, I have about 720 entries in the export, not sure how many comments.