Thanks for pointing out the example was out of date, we will upload the latest version asap.
The error is because incompatibility of spring versions or the presence of spring-asm.jar. If I recall correctly this the same error message as seen because of this: https://issues.jboss.org/browse/SNOWDROP-59. I believe you can rectify this by downloading the latest version of snowdrop with the spring modules: http://downloads.jboss.org/snowdrop/2.1.0.Final/jboss-spring-subsystem-as7-2.1.0.Final.zip, and using the spring version that matches the one your project uses.