miniposts,slidebar

alright,well im having a problem with both my miniposts and my slidebar.it says it requires categories to display content…i have categories but for some reason its showing up as blank when it wants me to pick a category from a drop down list to display the content,im sure its a problem with the coding but i dont know how to fix it,if anyone knows how to solve this problem please post here.

thanks,
batt