There's a weird mix going on here. The first error would imply a newer XML but the second error would imply an older one. The latter one makes me think you were trying to import the 1.1.2 XML which isn't compatible with the latest version of XF.
The first error would imply that the other files haven't been uploaded properly (the 1.1.7 version) or old versions are being held in the opcode cache. I'd try a reupload first.
I gave up on this and ended up upgrading XenForo Enhanced Search then did the forum from 1.5.7 to 1.5.8. I thought I'd try the gallery .xml file again after that and it upgraded (I didn't reupload it) . All done now.