Not possible to enable image gallery

Hi

I'm trying after updating a site from D6.22 to D7.10 to migrate content made with the image gallery in D6 & especially the image gallery.
The problem is it is not possible at all to enable the image gallery as I keep getting this error message:

Fatal error: Call to undefined function taxonomy_save_vocabulary() in /home/que1/public_html/abc/sites/default/modules/image/contrib/image_gallery/image_gallery.install on line 34

After initially failing to use the file converter & image legacy modules, I managed to run it, this time with no errors BUT as said without the image gallery.

So my question is: how do I avoid this error so I can ultimately be able to access the image gallery & its content or the only way out is to create a completely new one from scratch? :(

I would appreciate any help.
[Not a coder]

Regards