In the memcache PECL extension version 2.2.5, the delete function does not work with memcached 1.4.3. To work around this, here is a version of the memcache PECL extension with a patch provided by harv at pringo dot com applied:
http://code.google.com/p/phpmemcachepatch/downloads/list
To install: download
http://phpmemcachepatch.googlecode.com/files/memcache-2.2.5b.tgz
and do:
pecl install memcache-2.2.5b.tgz