MyBB Community Forums

I'm hoping I'm posting in the right place. My site is thevisionaryvocalistforum.com

I try to log into my admin, and I get:

Not Found
The requested URL /admin/index.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Is there a way I can resolve this on my own?

Sounds like the files are missing, a 404 just means the file or folder isn't found.

It looks like your ./cache/ and ./cache/themes/ folders aren't writable either, which is why your forum has no styles.

It also seems that you have removed the MyBB Powered By notice so we can't assist you any further.