Yes, that does work for text files. I should have mentioned these are pdf files. ie/acrobat intervenes in their handling leaving Mechanize with no content.
You get this error if you try $ie->content
Can't use an undefined value as a HASH reference at C:/Perl/site/lib/Win32/IE/Mechanize.pm line 393.
which is:
sub content { $_[0]->{agent}->Document->documentElement->{outerHTML} }