Hmm, I forgot to mention I tested only with the Free To Play version on steam. It did not require any Origin account and never opened any Origin app to play.
Maybe there are additional launcher executables that run for Origin or subscriptions, that vorpX is mistakenly trying to hook first instead of the actual swtor.exe. The vorpX config app has an Excluded Programs list for this reason. Maybe try adding any additional exes you find in the games install directory to the vorpX excluded list, and click apply.
In my swtor directory I see launcher.exe, launcherDiag.exe, and launcherRestartMsg.exe. In my case it was enough that launcher.exe is among the vorpX excluded list, but it might be safer to add any and all others that you might find there.
vorpX should not initiate until after you have logged into the launcher and then press play.