I had to disable WP Achievements as it was causing me real issues. I also removed the Simple Press Achievements plugin but now none of the forum posts will show:
Fatal error: Call to undefined function wpachievements_getRankImage() in/problem-with-post-edit-buttonome/problem-with-post-edit-buttonowtonet/public_html/wp-content/sp-resources/forum-themes/problem-with-post-edit-buttonowtonetwork/templates/spTopicView.phpon line 185
That is clearly a customised Simple:Press theme. We do not use that function as standard so it was put there by yourself or a developer on your behalf.
If you feel you may one day reinstate WP Achievements then it should be wrapped in a function_exisrs() call. This is, actually, the way ALL calls to third party functions should be handled.
If you want to be rid of it for good then simply remove the function call.