As Carl pointed out, you can go through the official support website. Should you not be able to select tech support, due to the product not being registered yet, you can always pick the "sales" branch and place an enquiry regardless of your product registrations. This kind of query is perfectly fine with sales anyway. Not sure what the problem is with your disk and whether it has only become recently damaged or you never successfully installed from it in the first place, but if it's not a physical defect on the disc, support might be able to troubleshoot the installation.
If you still simply want to work around the issue by installing the downloadable version, here are the direct links: