First, Veeam Endpoint Backup requires at least Microsoft Windows Server 2008 R2 SP1 and that is the reason why it isn't able to install.
Second: Support for Veeam Endpoint Backup Free is also free, but comes without SLA. It is explained here: https://www.veeam.com/blog/technical-su ... -free.html
I do understand that you can't perform this procedure as the software isn't installed, and that is why we then normally work with the forums so that support can contact you directly. In the future, we will have different versions (including paid versions with different support options) where our support will be the same as for our other paid solutions. But unfortunately that won't solve your issue as that OS will not be supported.
PS: Could you tell me where it states in the user guide? I seem to be overlooking it but if it is not correct I can ask the technical writers to adapt it...
Hope it helps