We have discovered a case where one of the Visual Studio 2005 beta 2 Package Load Failure error dialogs will happen even after running the beta cleanup tool. If you installed VS 2005 beta 2 and unchecked the item named Team Foundation Client in the setup feature selection tree, you will see an error loading the package named Microsoft.VisualStudio.QualityTools.TestCaseManagement.QualityToolsPackage when launching the VS IDE.
To workaround this issue, you can locate the Visual Studio 2005 Team System Beta 2 - English item in the Add/Remove Programs control panel and launch setup again. Then check the item named Team Foundation Client and update your installation.
Please let me know if you have tried the cleanup tool and also installed the Team Foundation Client item in the setup tree and still see any Package Load Failures when using VS 2005 beta 2.