Hi Nafri,
Email protx support as they have had a few problems when the system got updated......in the mean time install the previous version....V1.16 - 2nd Aug.
This still uses the PREAUTH codes that protx are allowing vendors to use until 1st Sept.
At least this way you will still be able to take payments without any issues.
With V1.12-V1.17 there is no need to uninstall the previous version. (I know the instuctions said so, but this code was a small update and not a mojor one)
Just replace the protx_form.php file that is in catalog\includes\modules\payments with the one from the zip file.
This will save you a bit of time at least.
If you find that is was indeed protx that had not setup AUTHENTICATE AND AUTHORISE on your account properly, you can just copy over the same file from V1.17 again to update it.
If that doen't work, post a message backup again,
Cheers,
Michael.