invalid list template and untitled web parts after upgrade from sps2003

[tjho...@gmail.com]

I am currently working on a project upgrading a SharePoint 2003 site
to MOSS 2007. The original 2003 site is a single-server environment.
I have a virtual machine running that matches the environment of the
2003 server. I successfully used the SharePoint Backup and Restore
Utility to move the site from the original server to the virtual
machine. I ran prescan.exe without any errors, and I am now
attempting to do a gradual upgrade to MOSS on the virtual machine.

I successfully installed MOSS 2007 on the virtual machine and selected
gradual upgrade as my method of choice. I then started the upgrade
via Central Admin, starting with the root site. After the upgrade
process finished, I went to the site and got an error "Invalid list
template." I tried going to http://server/_layouts/settings.aspx to
get to the site settings page for the root site, and got the infamous
"Unknown error" page.

I tried upgrading another site (underneath the root site), and I also
got the "Invalid list template" error. However, I was able to access
the site settings page by manually entering in the /_layouts/
settings.aspx URL.

Also, I went to the Web Part Maintenance page for the second site by
manually entering .../sitename/default.aspx?contents=1. I noticed
here that all of the ListViewWebParts have "Untitled" as their title,
which is not the case in the 2003 environment. All of those web parts
have titles in 2003.

In the log files in the 12 hive, I am getting errors that read "Failed
to find <ListTemplate> tag corresponding to ID '104', tried both
onet.xml for site definition ID '20' language '1033' and global site
definition. Operation failed." and "Failed to determine the setup path
of the list schema for list template 104." There are also errors like
this for list IDs 103 and 106. From what I can tell, these IDs
correspond to the Links, Events, and Announcements lists, which are
default SharePoint lists as far as I know. I have scoured the
onet.xml files, and I have yet to find a list template with ID 103,
104, or 106 that does not correspond to Links, Events, and
Announcements.

Also, I think this might be related to users creating custom lists.
Sharepoint 2003 seems to create ListViewWebParts on the fly for custom
lists. These ListViewWebParts are the ones that appear to be the
problem. Although, this doesn't really explain the problem with 103,
104, and 106.

So... any ideas? I've googled all the relevant terms I can think of
and tried all the solutions I found, but nothing has worked.

Thanks in advance.