APK not building

Can anyone tell me why this isn't building - the log viewer doesn't seem to be giving me much of a clue other than:

"jar:file:/Applications/Stencyl/sw.jar!/res/logview4j/images/info.gif   false   INFO   1492261692578004628   stencyl.sw.util.StreamGobbler   [haxelib] /Users/richdowns/stencylworks/android-sdk/android-sdk-macosx/tools/ant/build.xml:281: null returned: 2
jar:file:/Applications/Stencyl/sw.jar!/res/logview4j/images/info.gif   false   INFO   1492261692578004627   stencyl.sw.util.StreamGobbler   [haxelib] /Users/richdowns/stencylworks/android-sdk/android-sdk-macosx/tools/ant/build.xml:899: The following error occurred while executing this line:
jar:file:/Applications/Stencyl/sw.jar!/res/logview4j/images/info.gif   false   INFO   1492261692578004626   stencyl.sw.util.StreamGobbler   [haxelib] /Users/richdowns/stencylworks/android-sdk/android-sdk-macosx/tools/ant/build.xml:887: The following error occurred while executing this line:
jar:file:/Applications/Stencyl/sw.jar!/res/logview4j/images/info.gif   false   INFO   1492261692578004625   stencyl.sw.util.StreamGobbler   [haxelib] /Users/richdowns/stencylworks/android-sdk/android-sdk-macosx/tools/ant/build.xml:885: The following error occurred while executing this line:

I've attached the logs

thanks

com.android.dex.DexException: Multiple dex files define Lcom/onemoreround/nightshiftv1/BuildConfig;

Try Run > Clean Project and see if that solves the problem.