If you work with big lists and experience an error message like "Java.lang.OutOfMemoryError: Java heap space", you have to allocate more memory to the Java Virtual machine (JVM). You can increase the minimum and maximum memory in file httpd.sh in directory /home/openemm/bin by expanding the args parameter like this:
args="[...] -J-Xms256m -J-Xmx768m"
If you have allocated all memory available and the error remains, you should increase your RAM to at least 1 GByte (better: 2 GByte) and modify the args parameter accordingly.