Serial number not being accepted during installation

[merrien40105227]

I purchased the CS5 Design Premium Student/Teacher version in 2011.  I have my code and serial number (which does match to my Adobe ID info).  I'm trying to install on a second computer which should be allowed per the EULA.  However, after having downloaded, the installation files from Adobe CS5 site, it won't accept my serial #.  It says it's not valid?

[Jeff A Wright]

Merrien40105227 to confirm you are utilizing the installation files available at https://helpx.adobe.com/creative-suite/kb/cs5-5-product-downloads.html?