well the coder of that template didnt use stylevars everywhere...
ACP => stylemanager
beside the stylename select another item in dropdownmenu..
select main css..
and there you are bound to find.. (in backgrounds etc..) more blackrazor_fire/... stuff
prefix it with your forums url like you did before..
there additionnally may be some other paths in the extra css part at the bottom of that page (Additional CSS Definitions)