Site dissapears after plugin activated

New to WP. My site https://www.deploymentlessons.org (still using their template until WP site is finished….if I ever get a plugin to work) is on a host site. I used FTP to download Akismet, All in one SEO Pack and cforms II to wp-content/plugins. The last is the one I really need. When any of the above are activated and I go to view site, the site is no longer there. The site returns when deactivated. It happens when I am using the base theme or a downloaded free theme.
Only other note is that at the bottom of the presentation screen, it states that the name of a broken theme is “images” and that the stylesheet is missing. But is doesn’t say which theme only images under the name.
Thoughts?