GetRowStatus,DB_ALTERED,ADDROW,UPDATEROW

I have a web application writing to an AS/400 file on the backend using ADDROW and UPDATEROW in lotus script.This seems to work most of the time.It fails once in a while.I have seen some of the information posted in the form but does no help.I get the result from GETROWSTATUS as DB_ALTERED and norm is DB_UPDATED(i guess).I have started logging some info to the agent log.What else can I do to understand what could be causing this? Thanks