Oracle Data Modeler: unable to create Java instance

The following error was displayed during the start of Oracle SQL Developer Data Modeler (v3.3.0.734) on Windows:

Unable to create an instance of the Java Virtual Machine
Located at path: ..\..\jdk\jre\bin\client\jvm.dll

This could be fixed by editing the file datamodeler\bin\datamodeler.conf :
try to change the following line
AddVMOption -Xmx768M
to
AddVMOption -Xmx512M

and restart Data Modeler after this.