Insert Statement is not working in production server

Hi experts,

I have one program( Test certificate printout program). After giving my input when i run the program . Some data is saved into one ztable. Its working fine till 2 months before. Now its not working, i mean  when i run the program, the data is not getting saved into my table. The code which i have written for insert query is executing but it shows no effect. Please give me some suggestions.

My code:

insert zqm_tb_is1786n FROM table final2 ACCEPTING DUPLICATE KEYS.

Hints: 

1) the internal table final2 having the values perfectly.

2) This code is working fine in quality server.

Thanks and Regards,

Linganathan.K