An unexpected error occurred.

Getting this message when trying to upload images to the gallery:
“An unexpected error occurred. This is most likely due to a server misconfiguration. Check your PHP error log or ask your hosting provider for assistance”

Contact our host and got this response:
“We have tested the upload method with the gallery and it does appear to be an issue with the plugin itself. We have confirmed that the settings and permissions are correct on the server and we are able to upload images using the wordpress media uploader without any issues. You may check with the developer of the plugin to see why the error is occurring and to be sure that it is compatible with servers running suphp as your server does.”

http://wordpress.org/plugins/nextgen-gallery/