Conga on RHEL 5 gives a 'Site Error' when attempting to administer a cluster

Issue

• The service luci gives the following error when attempting to administer a particular cluster (other clusters can be managed with the same luci server):

2009-07-17T14:38:42 ERROR Zope.SiteErrorLog https://somelucihostluci/luci/cluster/index_html  
Traceback (innermost last):  
Module ZPublisher.Publish, line 121, in publish  
Module Zope2.App.startup, line 240, in commit  
Module transaction._manager, line 96, in commit  
Module transaction._transaction, line 380, in commit  
Module transaction._transaction, line 378, in commit  
Module transaction._transaction, line 433, in _commitResources  
Module ZODB.Connection, line 484, in commit  
Module ZODB.Connection, line 526, in _commit  
Module ZODB.Connection, line 553, in _store_objects  
Module ZODB.serialize, line 407, in serialize  
Module ZODB.serialize, line 416, in _dump  
RuntimeError: maximum recursion depth exceeded