Hi Casey,
So you are upgrading from SharePoint 3.0 to SharePoint 2010. So you are moving the databases from the former SharePoint server to the new server where SharePoint 2010 is installed, since the new install and BP 5 must be on a 64 bit machine. These steps may help.
Steps to Upgrade BP 4.0 & BP 4.0 FP1 to BP 5.1 on SharePoint 2010
1. Setup BP 4.0 or BP 4.0 FP1 and then uninstall BP, but leave the SQL data in the databases.
2. Run SQL Commands on SL databases:
a. DBCC CHECKDB
b. DBCC CHECKCATALOG
3. Backup the SL and WSS_Content databases.
4. On another machine, setup Windows Server 2008 (or R2) x64
5. Setup SQL Server 2008 (or R2) x64 if not using a dedicated SQL Server 2008 (or R2) server.
6. Install SharePoint Foundation or Server 2010 using Server farm configuration.
a. Note: Don’t do the standalone installation as that will install a special version of SQL Server that will make working with the WSS_Content databases more difficult.
7. Make sure to create the Web Application that you want to attach the WSS_Content database.
a. Note: You don’t need to create the default site collection.
8. In SharePoint Administration, remove the content database from the Web Application by using the Manage content databases page. With the proper Web Application selected, click the WSS_Content database, scroll to the bottom of the page, check the Remove content database checkbox, and then click the OK button.
9. Restore the BP 4.0 (or FP1) databases including the WSS_Content database.
10. Open the SharePoint 2010 Management PowerShell console from the start menu under the SharePoint 2010 Products folder.
11. Test the WSS database by running Power Shell command “Test-SPContentDatabase -Name <DatabaseName> -WebApplication <URL>”.
a. Example: “Test-SPContentDatabase -Name WSS_Content -WebApplication http://localhost”
b. NOTE: You will get a bunch of errors because the BP features are missing, ignore these errors.
c. If the SQL Server is not local, then will need to specify. Refer to SharePoint Documentation for additional arguments required.
12. Run the PowerShell Command “Mount-SPContentDatabase -Name <DatabaseName> -DatabaseServer <ServerName> -WebApplication <URL> [-Updateuserexperience]”
a. Example: “Mount-SPContentDatabase –Name WSS_Content -DatabaseServer LOCALHOST -WebApplication http://localhost -Updateuserexperience”
b. NOTE: You will get a bunch of errors because the BP features are missing, ignore these errors.
13. Using the SL 2011 build, upgrade the SL Databases and register modules.
a. If the SL databases were moved to a different SQL Server, then the BusinessPortalUser account will be orphaned in the SL App and System databases, you must either remove that user from each database or choose a different user account in the BP install.
14. Setup BP build.
Let me know if you have additional questions.