No such file or directory- Simple Link Error Help?

[ETweedale]

I added

INCLUDEPATH += -I"x:\Cerulean_\Core\element.h"

INCLUDEPATH += -I"x:\Cerulean_\Core\element.h"

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and so on... to the .pro file but still get the same error:

Core/element.h: No such file or directory

I haven't done any explicit INCLUDEPATH before so I'm not sure if I got it right yet and couldn't tell from the online help stating:

-I <string> ........ Add an explicit include path.

Thanks for your help.