PWA errors after failed SP2a install

[Berry at JSO]

My SP2a install failed on the Project 2003 server, so I rolled back my
ProjectServer database to pre-SP2a.
Now PWA on my Project 2003 server throws a 500 error (from the log):
2006-09-26 19:54:19 n.n.n.n GET /ProjectServer/Admin/Admin.asp
|17|ASP_0223|TypeLib_Not_Found 80 <domain>\<user> n.n.n.n
Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2;+SV1;+.NET+CLR+1.1.4322)
500 0 0

I have run iisreset and rebooted my Project 2003 server.
How can I get my pre-SP2a configuration back online?
TIA,

 

[Berry at JSO]

Note that the log entry from my former post was from an attempt to access the
"configure project server" link from the project server.
PWA access attempts show the same 500 error and "typelib not found" string
against the LGNINT.ASP file rather than the admin.asp file.