Would you mind updating components/modules/tcadmin/api/tcadminapi.php line 68 from:
if ($host_name_output != false) {
to
if ($host_name_output != "<?xml version='1.0'?><document></document>") {
The visit the page again and post the log.
It looks like the module has an bug with logging errors properly, I've created a task on github to fix this.