You've obviously been to the Directgov website but you seem to have missed a vital piece of information:
"To qualify for SMP you must have been employed by the same employer continuously for at least 26 weeks into the 15th week before the week your baby is due (the qualifying week)"
http://www.direct.gov...pchildren/DG_10018741
Since the '15th week before' was around Christmas, and you only started work with your current employer in August (assuming that '16.08.2012' should actually read '16.08.2011'), you fail to meet the '26 week rule'.
However while you don't qualify for SMP, you should qualify for SMA:
http://www.direct.gov...pchildren/DG_10018869
So, instead of completing form MATB1, you should have used form MA1:
http://www.dwp.gov.uk...imforms/ma1_print.pdf
Chris