You should check that there are not connectivity problems from the client to the server before testing the connection via OpenJPA.
First, you should check the database name. You wrote 'MyDBInstance' and it has more that 8 characters, and DB2 databases have a max of 8. I hope this is not the problem.
I could see that the driver is refusing the connection:
Caused by: com.ibm.db2.jcc.am.DisconnectNonTransientConnectionException:
[jcc][t4][2043][11550][3.64.82] Exception java.lang.reflect.InvocationTargetException:
Error opening socket to server xyz.com/11.11.111.11 on port 62,000 with message: null.
ERRORCODE=-4499, SQLSTATE=08001
From Java, the connection problems are not very clear to detect. This error message says nothing. You should check that there are not firewall issues. For example test the port via:
telnet xyz.com 62000
or
telnet 11.11.111.11 62000
Once you can verify the port is open, you can use the DB2 driver directly to check the connection to the database with the Java driver
${DB2_DIR}/java/jdk64/bin/java -cp ${DB2_DIR}/java/db2jcc4.jar:${DB2_DIR}/java/db2jcc_license_cu.jar com.ibm.db2.jcc.DB2Jcc -url jdbc:db2://xyz.com:62000/MyDBInst -user myuser -password mypass
For more information about using the driver to test the connection: http://pic.dhe.ibm.com/infocenter/db2luw/v10r5/topic/com.ibm.db2.luw.apdv.java.doc/src/tpc/imjcc_rjv00004.html