I had a similar problem with GoDaddy share host. And it turned out the problem was with the .htaccess
In the WebRoot folder the .htaccess looks like this:
Options +FollowSymLinks
IndexIgnore */*
RewriteEngine on
# for GoDaddy
Rewritebase /
# if a directory or a file exists, use it directly
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# otherwise forward it to index.php
RewriteRule . index.php
Note the ‘for GoDaddy’ line, that’s what has to be added to make that error 500 go away though I did’t need it on my dev server.