VQMod DOMDocument

I to all,
I have moved my Opencart from an internal server (debian 8 32 bit) to another server (Debian 9 64bit, PHP7) and I get the following error:

VQMod::bootup - ERROR - YOU NEED THE PHP "DOMDocument" EXTENSION INSTALLED TO USE VQMod

Verified with phpinfo()

dom
DOM/XML enabled
DOM/XML API Version 20031129
libxml Version 2.9.4
HTML Support enabled
XPath Support enabled
XPointer Support enabled
Schema Support enabled
RelaxNG Support enabled

Running the installation of VQmod give me

VQMOD ALREADY INSTALLED!

What could it be?

Regards

Gian Carlo

VQMod::bootup - ERROR - YOU NEED THE PHP "DOMDocument" EXTENSION INSTALLED TO USE VQMod

Server specs specified, no OC version provided. Contact your host to install the DOMDocument server library.

Hi straightlight,
OC version is 3.0.2.0

In the meantime I have found the problem:

In debian 9 the the site directory is no more var/www/mysite but www/html/mysite

I have changed all the reference including the "html" in config.php and admin/config.php
I also changed the IP to the new one

And at the end I uploaded the exported DB that I didn't upload before.

Now the site is working ok. Strange because I didn't get a DB error on the HTML page.

Gian Carlo