VB6 Package Installation Problem – C:\Windows\Temp\Msftqws.pdw\$(DllSelfRegisterEx) Could not be Registered because it was not Found

If you find this error while installing legacy system built on VB 6.0 then you just need to go to setup.lst find DllSelfRegisterEx and replace it with DllSelfRegister and of course save it and then run the installation wizard again.

Reference: Source