Admin – stuck with error: Fatal error: Call to undefined function

BGMP 1.10.3 actually requires WordPress 3.5 in order to run, even though the documentation says it only requires 3.1. That’s a mistake on my part, and I’ve fixed it for the next version.

To solve your issue, you were right that deleting the plugin via FTP is a good temporary solution to restore access to wp-admin. It sounds like you may have only deleted part of the plugin, though, because the Failed opening required [...] views/message.php error can only happen if the basic-google-maps-placemarks.php and core.php files exists and are running. Make sure you delete (or just rename) the entire directory.

To be honest, though, if you’re running WordPress 3.3, you’ve got much bigger problems than not being able to access wp-admin. There are known security vulnerabilities that exist and have been fixed in newer versions. If you’re running 3.3, you’re basically asking to be hacked, if you haven’t been already.

The real solution to your problem is to update to the latest version of WordPress. If you don’t have the access needed to do it, then I’d urge you to find someone who does. (It sounds like you have FTP access, though, which should be all you need).

It’s also a very bad idea to have PHP’s display_errors setting enabled (which is what makes those fatal PHP errors show up on the page, instead of being logged to a file on the server). That can leak sensitive information to hackers. You can disable that in your php.ini file, or contact your hosting company for help. If they have it enabled by default, then I’d also recommend finding a new hosting company, because that shows they don’t know or care about basic security hardening.