Undefined function add_contextual_help() blocks Dashboard

I have an install of WP 3.1.3 that works fine with the default theme. However, when I activate the theme I want to use* and try to access the dashboard, I see this error in my Chrome browser: “Fatal error: Call to undefined function add_contextual_help() in …/wp-admin/widgets.php,” and the following message in Safari & Firefox: “Cheatin’ uh?”

*The theme I want to use is RefreshWP downloaded from https://theukmap.com/preview.php?type=wordpress&theme_id=1437

After reading WP forum posts, I’ve tried the following to find the source of the error, but no luck yet:

1. checked for missing call to wp_footer() in footer.php
2. disabled the plugins by renaming their folder
3. completed a full manual install of the latest WP version
4. replaced each of the main template files (header, index, sidebar, footer, comments) with ones from the default theme.

Any ideas for what to do to locate & fix the source of this problem?
(There are not posts yet, so no need to backup the db at this point.)

Thanks