register_globals affects File Uploads?

Does anyone know why setting register_globals=Off in php.ini disables file
uploads? It would seem to me that the file data would be in $HTTP_POST_VARS
if track_vars=On regardless of what register_globals is set to...it also
states in the PHP docs that the image data would be in $HTTP_POST_VARS as an
array in the multiple file uploads section.

Current Settings:
variables_order = "GPCSE"
register_globals = Off
track_vars = On
register_argc_argv = Off

Anyone have any idea on a workaround?

-Dave