SPF installation just exits with an error: “PROBLEM – The Install can not be completed”.
The message from JavaScript console is the only additional piece we could find. It may be related, or then not. Unfortunately, I have no expertise to debug this myself, since I’m not a programmer.
Could it be possible for you to install the Shopp plugin and test if you can reproduce the error? Maybe it tells more to you than to me? https://shopplugin.net/download/