segmentation fault problem

I hope someone can help me. I have been experiencing an exasperating problem while running a production 4gl program on our NCR 3450. The program craps out with a msg saying 'segmentation fault.' I have no idea where to begin looking for a solution to this intermittent problem. Below is the section of code that I have been able to narrow down as the problem area. Machine specifics are: NCR 3450, dual 486 33 mhz processors with 512MB RAM open sel_cur fetch sel_cur into l_flg, l_count if status = notfound then LET xmesg = " Customer Chain/Store Not Found " return -1 , lr_custf1.custno_mstr,lr_custf1.cusnam end if while (status = 0) if l_count > 1 then LET xmesg = " " LET xmesg = " Cust Chain/Store Not Unique " return -1 , lr_custf1.custno_mstr,lr_custf1.cusnam end if if l_flg = "R" then exit while end if fetch sel_cur into l_flg, l_count end while Any thoughts or comments would be greatly appreciated. If you need any other info I can provide that too. thanx, Keith McGregor