Fatal error: Allowed memory size of 8388608 bytes exhausted

It appears that your web server restricts Php scripts to using a maximum of 8 megabytes of RAM. This is an unusually low limit for a web server, and it's resulting in a memory shortage. I recommend contacting your web host's tech support to request that they increase the Php MEMORY_LIMIT configuration setting for your site.

If they refuse to increase the memory limit, you may consider switching to a less restrictive web host. One that I would suggest is ThinkHost (http://www.thinkhost.com/) - that have full Php support and plans starting at $9.95 per month.

One thing that you can do in the short term to free up some memory is delete some or all of your sites that are set to the status "Removed".