I agree with CF, DBP works much better with .x format than .3ds (which is a dying format anyway)...
Quote: "I want to use Sketchup is the large number of pre-made items that come with the software "
most of us don't use a lot of pre-fabs from other people (meaning we make our own stuff / and re-use the core models to tweak into other things)... So I understand your reasoning...
Look up lithunwrap or milkshape both of which can import .3ds files and convert to .x format, there are others that are better - I only listed these two because the first one is free and the other is about $30.00