Hi,
My name is David, and my company, Develop CENTS, provides web hosting, server administration services and IT consulting. I'm extremely familiar with WordPress, and most of the websites I manage for my various clients are on WordPress.
Our company website is on WordPress (developcents[.]com), as is my personal blog (davidmartinwhite[.]com) and my wife's blog (eastofthelake[.]com).
It would make my life much easier if you can provide SSH (shell) access to the server, but chances are very likely that I could fix your 500 error without SSH access.
I look forward to working with you!
Sincerely,
David White