You need to identify what constraints exist on the table, and then look at your SQL statement to see what you are not providing.
Is there an SQL statement I can write in i Navigator that will tell me what the contraints are? I've looked at the table in Access and don't see any requirements that I'm not fulfilling with records. I'm also doing this by pasting the data from Excel and not writing an SQL statement to do it.
Given the error message it looks like you are linked to the table via ODBC and the source is IBM DB2. You will have to go to the source to identify the field constraints.