overstay in schengen and now re-entry

hi
i overstayed in belgium with a tourist schengen visa in 2006 ( I was not aware i overstayed because i thought it depends on the validy period)
wen I left Belgium, the immigration officer didnt say anything, he just said i overstayed, thats all
Now i have to go back there on a business trip, I wanted to know if I will gain entry in there or not


thanks a lot
shane