WordPress Import White Screen

Hi,

I'm trying to install a WordPress export, I can get as far as choosing the authors and selecting upload file attachments but I can't go any further and the import fails. I just see a white screen.

The URL for the white screen is: /wp-admin/admin.php?import=wordpress&step=2

If I go back I see an error page:

Sorry, there has been an error.
File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini or by post_max_size being defined as smaller than upload_max_filesize in php.ini.

The file definitely isn't empty and below is my php.ini:

upload_max_filesize = 128M
post_max_size = 128M
memory_limit = 128M
max_execution_time = 600
max_input_vars = 10000
max_input_time = 400

Please help!

Thanks,
B