PCR problem - can not get the target SSR band (Jan/08/2004 )

I tried different concentration of DNA template, different Taq, most of time i only get huge band larger than 2000bp, soetime got 500 bp band, while i am looking forward the 200bp band.
what happened?

could you provide more info about your pcr? What is your template? genomic PCR or RT-PCR?