Msg 241, Level 16, State 1, Line 10

I have linked server of DB2. While i m trying to execute this query in SSMS

UPDATE OPENQUERY (DB2PAVAN, 'select column1 from catalog.table WHERE C_JOB = ''USER''') SET column1 = 'current timestamp';

I am getting error Conversion failed when converting date and/or time from character string.

Can you suggest me some method to resolve it?