WF Portal error The ASSERT condition was violated .WS10400022 (Contract alert)

Dear Experts,

We have implemented WS10400022 contract alert workflow in SRM environment.

Work item is visible in approvers portal inbox .On executing work item from portal we are getting below message.

Please suggest if we are missing some task specific setting or some activities to be performed.

mled1a11

ASSERTION_FAILED

The ASSERT condition was violated.

Method: GET_FMD_ITEM_APPROVAL_STATUS of program /SAPSRM/CL_APF_MD_PROV_V1X====CP

Method: /SAPSRM/IF_PDO_META_CONSUMER~GET_FIELD_METADATA of program /SAPSRM/CL_APF_MD_PROV_V1X====CP

Method: /SAPSRM/IF_PDO_META_CONSUMER~GET_FIELD_METADATA of program /SAPSRM/CL_PDO_META_BO_CTR_ADVCP

Method: /SAPSRM/IF_PDO_META_CONSUMER~GET_FIELD_METADATA of program /SAPSRM/CL_PDO_META_HANDLER===CP

Method: UPDATE_META_DATA_ELEMENT of program /SAPSRM/CL_CH_WD_MAP_META_HDLRCP

Method: UPDATE_META_DATA of program /SAPSRM/CL_CH_WD_MAP_META_HDLRCP

Method: REFRESH_ROWS of program /SAPSRM/CL_CH_WD_DOTM_CTR_ITEMCP

Method: /SAPSRM/IF_CLL_MAPPER~REFRESH of program /SAPSRM/CL_CH_WD_MAP_DO_TREE==CP

Method: /SAPSRM/IF_CLL_MAPPER~REFRESH of program /SAPSRM/CL_CH_WD_DOTM_CTR_ITEMCP

Method: WDDOMODIFYVIEW of program /1BCWDY/0O2TMWINODEGC18LL6O7==CP

Thanks

Aditya