I was having the same problem with WordPress 2.8.4. However, I had an older version of Meta Robots on my computer 3.07) and I tried what pepsirules2k mentioned:
- Delete your current Robots Meta installation
- Upload an older Robots Meta plugin -- so far 3.0.11 and 3.0.7 work for this
- Upload the older Robots Meta plugin to your WordPress plugins folder and activate it
At this point, you can verify that the older plugin is working, and if it is -- upgrade (automatically is how I did it) to the newest version. This worked for me.
I'm not sure where you can get outdated wordpress plugins, though -- I searched for a while online and then finally looked through one of my backup folders & found the older plugin.
Also, a while ago I couldn't get Robots Meta to work, and I discovered that my theme didn't include wp_head call in the header. So, if the above doesn't work for you, be sure that this:
<?php wp_head(); ?>
is in your header.php file.
Actually -- one more thing. Several themes that I've used lately have included the meta robots tag in the header.php file by default, and it always shows meta_robots=index,follow. You'll want to check the header.php to be sure that the meta robots tag isn't hard-coded into your theme's template.