what version of vb? It looks alot newer than 3.0.12
I would double check your using the correct versions with the correct versions of vb. Older software which has not been used in many years is not really designed for newer PHP versions which could be an issue.
Your vb copyright says 2013 and the lowest version of vbGallery we release is 2.42 for vBulletin 3.6 series.
vbGallery 1.02 is for vbulletin 3.5 so I know you can not be running vbulletin 3.0.12. I do not think you understand what I am saying. vbGallery came into existence around April of 2006 and was never even a thought when 3.0.12 came out well over a decade ago or more. There is a 3.6.12 of vbulletin. I have checked the members area of vb and am very sure of what versions they released.
Your talking about a piece of software that was released 7 years ago and is not designed to run on servers nowadays. Your only option is to upgrade. Before you do that though you really need to know exactly what version of vbulletin your running like I said real old vb forum software is not going to have a copyright of 2013.
We do not release or support vbGallery 1.02 anymore. Our lowest support version of vbGallery 2.42 for vbulletin 3.6