I have upgraded my Microsoft Office SharePoint Server 2007 to Service Pack 1 and restored a backup from the portal made with the RTM version, which included the Project Server 2007 install.
After restore, the Project Server 2007 database schemas remained in the RTM version, and I tried to run the SharePoint Products and Technologies Configuration Wizard to make the database schemas upgrade, but it didn’t.
The next step was reaplying the Service Pack 1, but the installer told it was already installed, so I extracted the install files with the /Extract: argument and ran the pjsrvappwwsp1.msp file.
This procedure executed the schema upgrade and my Project Server is fully functional.
You can check your current Project Server 2007’s database schema version by following the tips at the Steven Haden’s blog: http://blogs.msdn.com/shaden/archive/2008/01/10/migrated-to-sp1-checking-your-database-schema-version.aspx.