XML Parsing Error: xml processing instruction not at start of external entity

[Scandal]

Thanks Dave!! Your post inspired me to take a better look @ config.php.

The issue was that we were talking about a vB3.8.4 with a config.php of version vB3.6.8!

It seems the admins were upgrade all the time the vBulletin with not touching the config.php.
Maybe was it or maybe cause the file was some enters and spaces from the lots times of editing all these years.

I just replace the config.php with clean a vB3.8.7 ++ applied again the information.

All good, thank you very much