6
If I remember correctly, extGallery had a hacked file that was overwriting a XOOPS native file.
My guess is that you have installed extGallery in the past, and then removed it, but the hacked file remained.
Use Filecheck from your original XOOPS version to find out which files are different.
Or check in extGallery which file(s) were patched, and then copy back the original ones from whatever XOOPS version you have.