When performing a promotion, I get the following stacktrace (changed project name to "myProject" as this is a public forum). This is shown in the configuration log for the E2E folder as per below.

java.lang.RuntimeException: ognl.MethodFailedException: Method "convertVersionToLabel" failed for object root.myProject.projects.E2E [java.lang.NullPointerException]
at com.pmease.quickbuild.model.Configuration.evaluateStringExpression(Configuration.java:901)
at com.pmease.quickbuild.model.Configuration.getVersionForNewBuild(Configuration.java:974)
at com.pmease.quickbuild.model.Configuration.promote(Configuration.java:1163)
at com.pmease.quickbuild.triggeringinstance.PromoteTriggeringInstance.execute(PromoteTriggeringInstance.java:30)
at com.pmease.quickbuild.model.Queue$BuildRunner.run(Queue.java:240)
at java.lang.Thread.run(Thread.java:595)
Caused by: ognl.MethodFailedException: Method "convertVersionToLabel" failed for object root.myProject.projects.E2E [java.lang.NullPointerException]
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:796)
at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:61)
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:819)
at ognl.ASTMethod.getValueBody(ASTMethod.java:75)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
at ognl.SimpleNode.getValue(SimpleNode.java:210)
at ognl.Ognl.getValue(Ognl.java:333)
at com.pmease.quickbuild.model.Configuration.evaluateStringExpression(Configuration.java:898)
... 5 more