opencart_seo_pack_pro_v.9.61 installation problem

I've used this module for years and have liked it. I caused a complete website crash lately and had to restore it from backups. All the modules except this one came along with restoration. I downloaded it again, added ocmod.zip to the end of the file name and got an "invalid file type" error when I tried to install it. The same thing occured without the addition. What could I be doing wrong?

This is an issue caused by the 3rd party commercial SEO extension, hence you should really ask the author for support.