Currently I have the following versions:

apr: 0.9.18
apr-iconv: 0.9.7
apr-util: 0.9.17

I've renamed all of them to their respective names in the same directory as the build instructions require.

I go to the apr-util directory and execute:

nmake /f aprutil.mak

It looks like things build normally until I see this (Note that this is just a snippet from the very bottom of all the output, there is far more above but I have left it out):

        if not exist ".\Debug/" mkdir ".\Debug"
        cl.exe @C:\Users\VOID~1.POI\AppData\Local\Temp\nm46D1.tmp
        link.exe @C:\Users\VOID~1.POI\AppData\Local\Temp\nm46F1.tmp
        cd ".."
        cd ".\..\apr"
        "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\BIN\nmake.exe" /
                  /F .\apr.mak CFG="apr - Win32 Debug"

Microsoft (R) Program Maintenance Utility Version 9.00.30729.01
Copyright (C) Microsoft Corporation.  All rights reserved.

        cd "..\apr-util"
        if not exist ".\LibD/" mkdir ".\LibD"
NMAKE : fatal error U1073: don't know how to make '"apr.h"'

Notice the error at the bottom of the snippet above. Why is this happening?