Proguard error - Need help with proguard configuration

[vinaywadhwa]

When i try to build my app, which uses this library (Version 5.0), i get the following error during transformClassesAndResourcesWithProguardForRelease build step

Preverifying...
Unexpected error while performing partial evaluation:
 Class       = [com/stericson/RootTools/SanityCheckRootTools$SanityCheckThread]
 Method      = [run()V]
 Exception   = [java.lang.IllegalArgumentException] (Can't find common super class of [com/stericson/RootTools/SanityCheckRootTools$SanityCheckThread$2] (with 1 known super classes) and [java/lang/Exception] (with 3 known super classes))
Unexpected error while preverifying:
 Class       = [com/stericson/RootTools/SanityCheckRootTools$SanityCheckThread]
 Method      = [run()V]
 Exception   = [java.lang.IllegalArgumentException] (Can't find common super class of [com/stericson/RootTools/SanityCheckRootTools$SanityCheckThread$2] (with 1 known super classes) and [java/lang/Exception] (with 3 known super classes))
Warning: Exception while processing task java.io.IOException: java.lang.IllegalArgumentException: Can't find common super class of [com/stericson/RootTools/SanityCheckRootTools$SanityCheckThread$2] (with 1 known super classes) and [java/lang/Exception] (with 3 known super classes)
Thread(Tasks limiter_10): destruction

I have this in my proguard config already

-keep public class com.stericson.** { *; }
-keep class com.stericson.RootTools.** { *; }
-keep interface com.stericson.** { *; }
-dontwarn com.stericson.**

Can someone help?