Android Studioで Executing tasks実行中にjava.lang.RuntimeExceptionが発生する

初めての投稿なため、分かりづらい等あるかと思いますが、
ご協力のほど、よろしくお願いいたします。

Android StudioでKotlinの勉強をするため、環境構築を行っています。

Event Logで
13:09 Gradle sync start
13:16 Gradle sync completed
13:16 Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies]
が表示されているのですが、「13:16 Execute tasks...」が終わりません。

Gradle Consoleを見ると「java.lang.RuntimeException」が発生していました。
原因と対処法がわからないので、どなたかお力を貸してください。

他に必要な情報があれば、教えてください。

###Gradle Console

Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies]

Configuration on demand is an incubating feature.
NDK is missing a "platforms" directory.
If you are using NDK, verify the ndk.dir is set to a valid NDK directory. It is currently set to C:\Users\XXXX\AppData\Local\Android\sdk\ndk-bundle.
If you are not using NDK, unset the NDK variable from ANDROID_NDK_HOME or local.properties to remove this warning.

Incremental java compilation is an incubating feature.
:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAnimatedVectorDrawable2600Alpha1Library
:app:prepareComAndroidSupportAppcompatV72600Alpha1Library
:app:prepareComAndroidSupportConstraintConstraintLayout102Library
:app:prepareComAndroidSupportSupportCompat2600Alpha1Library
:app:prepareComAndroidSupportSupportCoreUi2600Alpha1Library
:app:prepareComAndroidSupportSupportCoreUtils2600Alpha1Library
:app:prepareComAndroidSupportSupportFragment2600Alpha1Library
:app:prepareComAndroidSupportSupportMediaCompat2600Alpha1Library
:app:prepareComAndroidSupportSupportV42600Alpha1Library
:app:prepareComAndroidSupportSupportVectorDrawable2600Alpha1Library
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources
Exception in thread "png-cruncher_1" java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at C:\Users\XXXXX\AppData\Local\Android\sdk\build-tools\26.0.1\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher$1.creation(QueuedCruncher.java:121)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:205)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "png-cruncher_3" java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at C:\Users\XXXXX\AppData\Local\Android\sdk\build-tools\26.0.1\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher$1.creation(QueuedCruncher.java:121)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:205)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "png-cruncher_2" java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at C:\Users\XXXXX\AppData\Local\Android\sdk\build-tools\26.0.1\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher$1.creation(QueuedCruncher.java:121)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:205)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "png-cruncher_4" java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at C:\Users\XXXXX\AppData\Local\Android\sdk\build-tools\26.0.1\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher$1.creation(QueuedCruncher.java:121)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:205)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "png-cruncher_5" java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at C:\Users\XXXXX\AppData\Local\Android\sdk\build-tools\26.0.1\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher$1.creation(QueuedCruncher.java:121)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:205)
at java.lang.Thread.run(Thread.java:748)