XF 1.5 Trying to install Media Gallery, getting error

[Soliloquy]

I'm trying to install Media Gallery, but getting the following error when I try to import the XML file from the server:

The callback class 'XenGallery_Option_Watermark' for option 'xengalleryEnableWatermarking' is not valid.

I also tried downloading the XML file from the server and using the upload tool, but that gave me the same error. Could this have something to do with the fact that I originally installed XenForo a couple of versions ago, but only got around to upgrading and installing Media Gallery recently?

 

[whynot]

Can you upgrade to the current XF version?

 

[Soliloquy]

I think I figured it out. It seems my FTP client didn't upload all of the files. It's processing now. Thanks!