JBoss BRMS 5.3.0 is unable to import DRL rules file. How to fix it?

Issue

JBoss BRMS 5.3.0 is unable to import DRL rules file. Here is a portion of the server exception:

10:31:25,353 ERROR [[PackageDeploymentServlet]] Servlet.service() for servlet PackageDeploymentServlet threw exception
java.lang.NullPointerException
    at org.drools.guvnor.server.util.ClassicDRLImporter.getRuleName(ClassicDRLImporter.java:245)
    at org.drools.guvnor.server.util.ClassicDRLImporter.parse(ClassicDRLImporter.java:70)
    at org.drools.guvnor.server.util.ClassicDRLImporter.<init>(ClassicDRLImporter.java:57)
    at org.drools.guvnor.server.files.FileManagerUtils.importClassicDRL(FileManagerUtils.java:313)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
    at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:32)
    at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
    at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:28)
    at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
    at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:77)
    at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
    at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
    at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
    at org.jboss.seam.security.SecurityInterceptor.aroundInvoke(SecurityInterceptor.java:163)
    at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
    at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
    at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185)
    at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103)
    at org.drools.guvnor.server.files.FileManagerUtils_$$_javassist_seam_6.importClassicDRL(FileManagerUtils_$$_javassist_seam_6.java)
    at org.drools.guvnor.server.files.PackageDeploymentServlet.doPost(PackageDeploymentServlet.java:101)