Symptoms
When you use a package that you created with the Package and Deployment Wizard (PDW) to install a Visual Basic application, you may receive the following error message (or similar) during the installation:

Unable to register MSADO15.TLBThis error message may reference any of the following files:MSADO15.TLBMSADO20.TLBMSADO21.TLBMSADO25.TLB
Resolution
The Package and Deployment Wizard adds the type library (.tlb) file to the package because the type library is referenced in your project. The PDW also erroneously assigns the $(DLLSelfRegister) registration macro to the type library in the Setup.lst file that is created for your installation package.
Most commonly, this problem occurs when your Visual Basic project contains a reference to a version of ActiveX Data Objects (ADO) that is earlier than the latest installed version. The reference for the latest installed version of ADO points to MSADO15.DLL. Earlier version references point to the above-mentioned ADO type library files.