I have my Adobe Creative Suite CS6 installed in my Mac, and would like to install the free version indesign CS2 at the same time. However, error comes out while installation is happening. How could I have both version of Indesign being installed?
There is no free version of InDesign CS2. What was posted was a means by which existing CS2 license holders could reinstall and activate their software.
Unless you specifically licensed CS2 yourself many years back, you are not legally entitled to install or activate this software. Also note that CS2-era software was never designed or tested on today's hardware and/or software configurations.