Fatal Error, out of memory

This problem is occuring on quillian.net, the Common Sense Economics blog. I do not know very many techincal terms and don’t write code other than cutting and pasting.

With the exception of Akismet plugins do not work on my set up. I get error messages like the one below when I try and activate a plugin.

Fatal error: Out of memory (allocated 11796480) (tried to allocate 6912 bytes) in /home/quillia/public_html/blog/wp-content/plugins/bbpress/includes/topics/functions.php on line 428

Also, anytime I load a plugin it seems to disable the media upload feature. A message comes up saying to try again in a few minutes. The file actually load but the image does not show up in the library/ It just shows the name of the file.

Some of these plugins would be useful if there is a way to get them working without disabling the rest of the program.