AS/400 TimeStamp

"Date, Time or Timestamp value is not valid (C G D F)."

How to Solve this problem. what could be the error?. as far as i think the date is available in the database.

How do I modify the value returned from current(time)

I have an AS/400 query that requires me to search records with a timestamp from 20 mins prior to the current system time. If I use the current(time) value in the query, how do I modify it to return a time 20 minutes earlier?

Remote access the login time stamp of user, where it is being stored by system

In case of AS/400 Remote access the login time stamp of user is being stored by system some where and displaying correctly, whenever required. Please let us know where this data is being stored and how to extract the same. Thanks, Gadang