I've just installed the latest version now I get this error:
{Tue, 17 Jan 2012 13:47:19 GMT} Zenphoto v1.4.2[8956]

  Backtrace: fatal zp_error:MySQL Query ( DELETE FROM `zenp_search_cache` WHERE `date`

The error speaks of two different tables "westensc_zenp2.zenp_search_cache" and "zenp2.zenp_search_cache". So what is your database prefix actually? Setup should create all needed tables.

If you did upgrade through one of the third party install helpers, please report this problem to them. It can only happen if the Zenphoto setup script was not used to properly migrate your installation.