With turnkey installer we have Java 1.8 update 74, you can try that. You should use pre-configured Jboss. Go through supportability matrix as well [1][1] https://helpx.adobe.com/aem-forms/6-2/AEM-forms-JEE-supported-platforms.html
Issue seems to be with JVM. Check[1],[2]. If you are using non-turnkey installer try to update Java.[1] http://stackoverflow.com/questions/25406681/jvm-crash-exception-access-violation[2]https://www.java.com/en/download/help/exception_access.xml
ES4 is not supported over Windows 2012. You should consider using AEM Forms 6.2(latest)[1]. You can either opt for OSGI or JEE based on your requirements.ThanksWasil[1] AEM 6.2 Forms Help | Supported Platforms for AEM Forms on JEE
I'm not sure whether Windows authentication for IMAP would work or not, but you can refer to sample[1] on how to use the Email startpoint correctly.[1] LiveCycle ES2 Service Samples - Standard Service - Email ThanksWasil
You can drag the processBtn from you WSDL data connection "Data View". Please follow the sample : LiveCycle ES2 Service Sample - Forms - Invoke Web Service From PDF Form ThanksWasil