I tried the foll. command from VB:

retval=shell("
sqlldr userid=scott/tiger@optxdb control="C:\temp\testheader.ctl" log="C:\temp\testheader.log"")

I even tried giving the path name for sqlldr like:

retval=shell("C:\oracle\ora81\bin\sqlldr.exe .........rest of the parameters here) , but both these formats do not work.

Thank you