Why can't my compiler find a file?

When I try to compiler jost (a JSON parser) I get a ton of errors, the first being jost/Array.hpp: No such file or directory.

I've imported all of the jost files into my project. They are located in Project\jost

I'm looking at the file that it says that can't be found. Why is this? Dev-C++, GNU C++ compiler. I shouldn't have to add anything to the linker because it's all source code, no library.

Check your Additional Include Directories. You may even want to put the particular directory in there even if it "should" be found normally, just to be sure.

did you include the files in the actual headder? also the including a dir is a good idea.