Might be that your installation of ARR is broken, and the disc does not recognize it, the disc installation is simple unpacker to be honest as I have the dvd heavensward as well, all it has is an install button and then it unpack it to your arr folder and make shortcut on desktop, from what I saw on the dvd you could very vell copy and paste those files yourself.

Now if you have problems after some 20MB patch that suggest that your game client might become damages. Might be a good idea to just remove everything. Reinstall the client, and then let the patcher download botch ARR and Heavensward from SE servers.