When you Publish to the Web in Pub 2003, you will get an index.htm file and
an index_files folder. The index.htm file is the home page, and is not
contained in the index_files folder which contains the other pages in the
site and the supporting graphics. You should upload both.

You don't say how you are uploading, so reference these sites for further
instructions:

Reference: How to publish a Publisher web in HTTP:
http://msmvps.com/blogs/dbartosik/pages/80557.aspx

How to publish a Publisher web publication (FTP) :
http://msmvps.com/blogs/dbartosik/pages/80556.aspx

How to trouble-shoot Publisher web upload issues :
http://msmvps.com/blogs/dbartosik/pages/80560.aspx

If you are using forms in your web publication, reference: Publisher web
publication forms 101:
http://msmvps.com/blogs/dbartosik/archive/2006/01/07/80564.aspx

If you choose to use FTP uploading then consider downloading and installing
the free FTP client FileZilla:
http://filezilla-project.org/  It is likely to be easier for you. Take the
time to also download the excellent documentation and read it.

Prepare, publish, and maintain your Publisher Web site:
http://office.microsoft.com/en-us/publisher/HA100947601033.aspx
It is written for Pub 2007, but if you are using IE7 instead of IE6, then
the directions for using Vista would apply. FTP uploading has changed with
the introduction of IE7.

DavidF