I'm not sure but if you manage to get it installed and registered on your home system then a download link might appear in your store account. I forget whether I got a dl link for my first Sonar version (X1 Pro Suite on DVD). If not they'll likely at the very least email you the downloads so if you can try to install at home tonight (to register and create an account) and call them tomorrow.
It does sound to me like an issue on that system whether through permissions, setup or other gack on the system. Sonar is a little more invasive than the usual app so perhaps it's fiddling with parts of the registry you you simply were not intended to.
Are the owners/admins of this computer aware of the fact you were going to attempt this install? Is this for like an a/v course or something? We had an issue a while back with a fellow trying to install it on a work or school system (I forget) and he really should not have been. IIRC it really ticked off one of more helpful members (Bob) who was going out of his way to get him going because the guy tried to hide that fact from us throughout a very long thread and wasted everyone's time. He was not supposed to be installing it and the system was set up to NOT allow such shenanigans and he couldn't disable stuff that was interfering with the program.
Not saying that's what you are doing and you seem to be being very upfront but it is quite possible there is a good reason the system isn't letting you do this.... because the owners don't actually want you to. Knowaddimean?
Either way, good luck. There are some other things you'll probably run into if you are trying to run Sonar on a laptop (especially if you don't have an interface) so even if it does install you may not be out of the woods yet. Just let us know. Lots of smart and helpful folks here.
And welcome to the forum. :-)