Caused by: java.lang.NoSuchMethodError: org.antlr.runtime.DFA.unpackEncodedString(Ljava/lang/String;)[S

at org.drools.lang.DRLParser.<clinit>(DRLParser.java:7302)

at org.drools.compiler.DrlParser.getParser(DrlParser.java:204)

at org.drools.compiler.DrlParser.parse(DrlParser.java:60)

at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:156)

at br.com.auster.rules.AbstractRulesEngineProcessor.addPackages(AbstractRulesEngineProcessor.java:349)

at br.com.auster.rules.AbstractRulesEngineProcessor.init(AbstractRulesEngineProcessor.java:254)

at br.com.auster.rules.InvoiceRulesEngineFilter.configureEngine(InvoiceRulesEngineFilter.java:201)

at br.com.auster.rules.InvoiceRulesEngineFilter.configure(InvoiceRulesEngineFilter.java:136)

.....

... 4 more

Any ideas of what could be happening?