The dzInstall.ini file is a configuration file used when a DAZ installer runs on the PC. It is used for many different products, not just DAZ Studio. The installer looks for this file (dzInstall.ini) for configuration information. When it does not find this file, it is supposed to create it.
In order for the installer to proceed, it needs to be able to find a valid dzInstall.ini file. To create this file, I'd like you to download and run the DAZ Bonus Content installer. This is free content that you can use (or not use) in Poser. This should create a dzInstall.ini file and then you'll be able to run the original installers.
You should be able to download the free DAZ Poser content installer from this webpage: http://www.download.com/3120-20_4.html?tg=dl-20&qt=DAZ%20Poser&tag=srch
If you do not find it there, then do a search on C-Net's website (www.download.com) for 'DAZ Poser' without the quotes.