NDKBuild Failure

I'm having trouble getting my NDK to compile properly in Android Studio. Whenever I try running to compile I am getting the following error.

Error:Execution failed for task ':app:ndkBuild'. A problem occurred starting process 'command 'ndk-build.cmd''

I have the following setup

And my build.gradle file is the following.

import org.apache.tools.ant.taskdefs.condition.Os

apply plugin: 'com.android.application'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.2"

    defaultConfig {
        applicationId "edu.uky.cs.www.diagramaphone"
        minSdkVersion 14
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"

        sourceSets.main{
            jniLibs.srcDir 'src/main/libs'
            jni.srcDirs = [] //disable automatic ndk-build call
        }
        project.ext.versionCodes = ['armeabi':1, 'armeabi-v7a':2, 'arm64-v8a':3, 'mips':5, 'mips64':6, 'x86':8, 'x86_64':9] //versionCode digit for each supported ABI, with 64bit>32bit and x86>armeabi-*
        android.applicationVariants.all { variant ->
            // assign different version code for each output
            variant.outputs.each { output ->
                output.versionCodeOverride =
                        project.ext.versionCodes.get(output.getFilter(com.android.build.OutputFile.ABI), 0) * 1000000 + defaultConfig.versionCode
            }
        }
        // call regular ndk-build(.cmd) script from app directory
        task ndkBuild(type: Exec) {
            if (Os.isFamily(Os.FAMILY_WINDOWS)) {
                commandLine 'ndk-build.cmd', '-C', file('src/main').absolutePath
            } else {
                commandLine 'ndk-build', '-C', file('src/main').absolutePath
            }
        }
        tasks.withType(JavaCompile) {
            compileTask -> compileTask.dependsOn ndkBuild
        }
        //ndk {
          //  moduleName "shape-detect"
            //cFlags "-DANDROID_NDK -D_DEBUG DNULL=0" // Define some macros
            //ldLibs "EGL", "GLESv3", "dl", "log"         // Link with these libraries!
            //stl "stlport_shared"                        // Use shared stlport library
        //}

    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:21.0.3'
    compile project(':libraries:tess-two')
    compile project(':libraries:opencv')
}

At this point I'm lost as to what can be wrong. I've followed several tutorials to try setting up the NDK to work properly, but I keep getting the error I showed above. Can anyone here provide some feedback on what I need to do in order to get the NDK to compile?