I assume these are not all happening at the same time.
What is the feed URL that is giving you 303's?
For the log file problem, try deleting all the files in the <tt>Logs</tt> directory. Also make sure the disk is not full and security permissions are OK (if you don't know what that means, as long as you can delete the files, you should be OK). Has it only started happening recently i.e have you been able to create channels in the past few days?