I’ve haven’t heard of that particular problem before. Do you see the ‘MapPress’ meta box (without the button) or is there no metabox at all?
Here’s some things to try:
- Check the MapPress ‘settings’ screen to see if you have the checkboxes set to include the editor for your post type (post and page should be checked by default).
- Deactivate ALL of your other plugins for a moment. If that fixes the problem, then reactivate them one by one to find the conflict.
- Reinstall the plugin: http://mappresspro.com/install
If the above don’t work please send me a login using the contact form, and I’ll take a look.