Warning (2): implode() [function.implode]: Invalid arguments passed [CORE/cake/libs/model/datasources/dbo_source.php, line 1468]

[okwme]

This error occurs every time i save model using the plugin.
it stil seems to work but i don't understand why implode gets invalid arguments.
full error report:

$query = array(
"offset" => null,
"joins" => null,
"fields" => array(
"COUNT(*)"
),
"table" => "contacts_events",
"alias" => "ContactsEvent",
"conditions" => array(
"ContactsEvent.event_id = Event.id"
),
"order" => null,
"limit" => null,
"group" => null
)
$model = AppModel
AppModel::$useDbConfig = "default"
AppModel::$useTable = "contacts_events"
AppModel::$displayField = "id"
AppModel::$id = false
AppModel::$data = array
AppModel::$table = "contacts_events"
AppModel::$primaryKey = "id"
AppModel::$_schema = array
AppModel::$validate = array
AppModel::$validationErrors = array
AppModel::$tablePrefix = ""
AppModel::$name = "ContactsEvent"
AppModel::$alias = "ContactsEvent"
AppModel::$tableToModel = array
AppModel::$logTransactions = false
AppModel::$cacheQueries = false
AppModel::$belongsTo = array
AppModel::$hasOne = array
AppModel::$hasMany = array
AppModel::$hasAndBelongsToMany = array
AppModel::$actsAs = NULL
AppModel::$Behaviors = BehaviorCollection object
AppModel::$whitelist = array
AppModel::$cacheSources = true
AppModel::$findQueryType = NULL
AppModel::$recursive = 1
AppModel::$order = NULL
AppModel::$virtualFields = array
AppModel::$__associationKeys = array
AppModel::$__associations = array
AppModel::$__backAssociation = array
AppModel::$__insertID = NULL
AppModel::$__numRows = NULL
AppModel::$__affectedRows = NULL
AppModel::$_findMethods = array
implode - [internal], line ??
DboSource::buildStatement() - CORE/cake/libs/model/datasources/dbo_source.php, line 1468
HabtmCounterCacheBehavior::_updateCounterCache() - APP/models/behaviors/habtm_counter_cache.php, line 402
HabtmCounterCacheBehavior::afterSave() - APP/models/behaviors/habtm_counter_cache.php, line 258
ModelBehavior::dispatchMethod() - CORE/cake/libs/model/model_behavior.php, line 171
BehaviorCollection::trigger() - CORE/cake/libs/model/model_behavior.php, line 494
Model::save() - CORE/cake/libs/model/model.php, line 1363
ContactsController::transformTags() - APP/controllers/contacts_controller.php, line 200
Dispatcher::_invoke() - CORE/cake/dispatcher.php, line 204
Dispatcher::dispatch() - CORE/cake/dispatcher.php, line 171
[main] - APP/webroot/index.php, line 83