Call to undefined function is_user_admin()
I get Call to undefined function is_user_admin() when I log into my wordpress installation. Info on the web suggests my account has probably been hacked. Should I just download the latest wordpress install and replace the wp-admin folder, or can InMotion restore a standard configuration for me?
That error comes from a version mismatch. This indeed could have been a hack that occurred in September of last year. I found the correct version of your WordPress and replaced the wp-admin folder with the correct files. You should now be able to log in without the error.
You will want to update your Wordpress as soon as you log in. There have been many security upgrades that you want to install.
I hope this answers your question. If you have any more questions or information specific to the issue please leave a comment below so we can further assist you.