Problems using SAPI with PHP through COM, on IIS - php

Question

I am attempting to get Text To Speech and Speech Recognition to work in PHP using Microsoft's SAPI through COM objects.
In the past, I already used this code to get TTS to work (Apache 2.1, PHP 5.5, on Windows 2003 Server)
// Instantiate the object
$VoiceObj = new COM("SAPI.SpVoice") or die("Unable to instantiate SAPI");
// Get the available voices
$VoicesToken=$VoiceObj->GetVoices();
$NumberofVoices=$VoicesToken->Count;
for($i=0;$i<$NumberofVoices;$i++)
{
$VoiceToken=$VoicesToken->Item($i);
$VoiceName[$i]=$VoiceToken->GetDescription();
}
// Get and print the id of the specified voice
$SelectedVoiceToken=$VoicesToken->Item(0);
$SelectedVoiceTokenid=$SelectedVoiceToken->id;
// Set the Voice
$VoiceObj->Voice=$SelectedVoiceToken;
$VoiceName=$VoiceObj->Voice->GetDescription();
$VoiceFile = new COM("SAPI.SpFileStream");
$VoiceFile->Open('./test.wav', 3, false);
// Speak to file
$VoiceObj->AudioOutputStream = $VoiceFile;
$VoiceObj->Speak("What an unbelievable test", 0);
$VoiceFile->Close();
On my new setup (IIS 7.5, PHP 7.0, Windows Server 2008R2) the same code fails at
$VoiceObj->Speak("What an unbelievable test", 0);
Fatal error: Uncaught com_exception: <b>Source:</b> Unknown<br/><b>Description:</b> Unknown in \\web\tts.php:30 Stack trace: #0 \\web\tts.php(30): com->Speak('this is a marve...', 0) #1 {main}
With such little detail (where to retrieve more?) I can't figure out what the problem may be.
Writing permissions checked.
PHP 7.0 replaced with 5.5, still not working.
Same code tested with a Win32 app, and it works flawlessly.
Any hints?

Answer 1

Two years later, I casually happen to find an answer to this problem.
PHP COM Objects can't perform file operations on network paths, even with all the required permissions
Once the development folders were moved on the same machine where IIS runs, a bunch of previously broken tests started working. They all had one thing in common: they were using COM interfaces to save files or something like that.