Was using Memcache and Memcached extensions, painfully bouncing between faults, failures and shortcomings of each.  My two cents: Neither of these old drivers has been a smash hit, repressing and slowly dooming of the true potential and full use of unix memcached.
The pain finally drove to me to try APC's apc_store and apc_fetch.  The results?  Instant success, no more errors, an order of magnitude (at least) speed boost, plus one less thing (memcached) to run.  Nice.  Never going back again.  Thank y'all.