T-Server Cisco : error in outbound preview

Hello,

When I Cancel an OCS outbound call via RequestRecordCancel in preview mode, I get the following error : ‘Attribute <GSW_CHAIN_ATTR> not found’

received from 65204(--)INCTIR01:3100(fd=392) message EventUserEvent
	AttributeAgentID	'1159'
	AttributeThisDN	'1259'
	AttributeUserData	[164] 00 05 00 00..
		'GSW_CALLING_LIST'	'CL_CCM_PREVIEW'
		'GSW_RECORD_HANDLE'	67
		'GSW_CAMPAIGN_NAME'	'CA_CCM_PREVIEW'
		'GSW_APPLICATION_ID'	130
		'GSW_AGENT_REQ_TYPE'	'RecordCancel'
	AttributeUserEvent	EventUserEvent
	AttributeTimeinSecs	1245826337 (08:52:17)
	AttributeTimeinuSecs	287000
	AttributeCustomerID	'Resources'
	AttributeEventSequenceNumber	00000000000004f2
08:52:17.287 Trc 50002 TEvent: EventUserEvent
08:52:17.287 OCSEvent[1476]::EventUserEvent(RecordCancel)
	TServer[175`T-Server_CCM]
	DN[997`1259]Extension
	Agent[140`Place_1259]
{
Attribute <GSW_CHAIN_ATTR> not found
08:52:17.287 Trc 50071 Send UserEvent
request to 65204(--) message RequestDistributeUserEvent
	AttributeUserData	[203] 00 06 00 00..
		'GSW_AGENT_REQ_TYPE'	'RecordCancel'
		'GSW_RECORD_HANDLE'	67
		'GSW_ERROR_NUMBER'	102
		'GSW_ERROR'	[b]'Attribute <GSW_CHAIN_ATTR> not found'[/b]
		'GSW_APPLICATION_ID'	130
		'GSW_CAMPAIGN_NAME'	'CA_CCM_PREVIEW'
	AttributeCommunicationDN	'1259'
..sent to INCTIR01:3100(fd=392)
} 

After reading the manual, I found that this argument is optional in this method :

Data Key         Type Key Required  Description
GSW_CHAIN_ATTR String No Flag determining whether to update the recordchain or just the single record. Values are AllChain (default) or RecordOnly.

Any ideas ?

Some help ?