Causing HTTP ERROR 500 on wp-admin

[rsgourley]

On a Bluehost-hosted site running PHP 5.2 the current version of the plugin prevents the admin from working, it gives a HTTP ERROR 500. The site itself appears fine (Magic Fields content working)

With a prior version of Magic Fields (2.3.1) , upload fields were not appearing so they tried updating. Wordpress and all other plugins were just updated to the latest version. Are there any known issues with the current version of Wordpress? Any other troubleshooting advice (besides looking for conflicts with other plugins?)

[rsgourley]

Actually, I've made some progress on this, but now on an admin page, where there uploaded button should be, I get:

403 Permission Denied

You do not have permission for this request /wp-content/plugins/magic-fields-2/admin/mf_upload.php?input_name=pdf_1_1&callback=mf_file_callback_upload&type=file

Permissions for admin/mf_upload.php seem fine.