I have discovered that whenever I delete a slave site that has been successfully created and configured, I get the following error for not only the JMS Multisites Joomla site, but ALL sites running on the same web server:

500 - An error has occurred.

Unable to load Cache Controller: callback

The front end of the master site shows:

"Infinite loop detected in JError"

We need to restart the web server in order to log back in our Joomla! sites.

We are using Joomla! 1.7.3 and JMS Multisites 1.2.68

The "Infinite loop detected in JError" joomla error message is generally correspond to a wrong DB connection parameters.
When Joomla has an error to connect on the DB, it tries to report an error that itself generate a error recursivelly.

Verify the DB connection parameters (host, DB name, DB user, DB password, DB prefix).