MuPDF force closes after few flips and returning w/o wait

java.lang.NullPointerException
at com.artifex.mupdfdemo.PageView.addHq in PageView.java on Line 606
at com.artifex.mupdfdemo.MuPDFReaderView.onSettle in MuPDFReaderView.java on Line 243
at com.artifex.mupdfdemo.ReaderView$2.run in ReaderView.java on Line 781
at android.os.Handler.handleCallback in Handler.java on Line 725
at android.os.Handler.dispatchMessage in Handler.java on Line 92
at android.os.Looper.loop in Looper.java on Line 176
at android.app.ActivityThread.main in ActivityThread.java on Line 5279
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke in Method.java on Line 511
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run in ZygoteInit.java on Line 1102
at com.android.internal.os.ZygoteInit.main in ZygoteInit.java on Line 869
at dalvik.system.NativeStart.main(Native Method)