Trouble with Release build

So I'm writing a program that uses dx7(i know it's old) with VC++ express 2010. I can build my project just fine in Debug mode. It compiles and executes. When I switch to Release mode however, I get this error:

Code:

1>DDFuncs.obj : error LNK2001: unresolved external symbol _DirectDrawCreateEx@16 1>DDFuncs.obj : error LNK2001: unresolved external symbol _IID_IDirectDraw7

I am new to 2010 version. Have I not included a directory somewhere or what? Thnks.