Are you installing Photoshop CS6 from a disc or did you purchase a download? Which operating system are you using? We do have Errors "Exit Code: 6," "Exit Code: 7" | CS5, CS5.5 - http://helpx.adobe.com/creative-suite/kb/errors-exit-code-6-exit.html but Exit Code 6 by itself is a bit generic. If you can provide the additional requested details it would be appreciated.
Disk, Win 7
Adobe support told me it meant I did not have adequate graphics card - so I pitched the printout of the error summary. I can redo install if necessary to recover complete error summary
Yes you would need at least 256 MB of Video RAM. You can find the system requirements for Photoshop CS6 at http://www.adobe.com/products/photoshop/tech-specs.html.