Resolution:
Environment:
==========
OS:All

Symptoms:
=========
The following error is thrown when starting TIBCO Administrator:

Error [Administrator] AESDKJ-0000 [main]  com.tibco.runtime.pool.ServerNotAvailableException: Server not available at address jdbc:sqlserver://hostname:<port>databaseName=<databasename
    at com.tibco.runtime.pool.impl.ConnectionPoolImpl.getAvailableObject(ConnectionPoolImpl.java:198)
    at com.tibco.runtime.pool.impl.ObjectPoolImpl.getObject(ObjectPoolImpl.java:219)
    at com.tibco.runtime.pool.impl.ConnectionPoolImpl.getObject(ConnectionPoolImpl.java:188)
    at com.tibco.runtime.pool.impl.ConnectionPoolImpl.getConnection(ConnectionPoolImpl.java:219)
    at com.tibco.runtime.pool.impl.ConnectionPoolImpl.getConnectionWithRetry(ConnectionPoolImpl.java:380)
    at com.tibco.pof.entitystore.db.DBEntityStore.init(DBEntityStore.java:456)
    at com.tibco.pof.entitystore.EntityStoreManager.a(EntityStoreManager.java:221)
    at com.tibco.pof.entitystore.EntityStoreManager.getEntityStore(EntityStoreManager.java:202)
...
Caused by: java.lang.UnsupportedClassVersionError: Bad version number in .class file
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)

Cause:
=====
In the TIBCO Administrator tra file, the JVM and JAVA environmental variables are pointing to the JRE 1.5.0 directory.

Resolution:
========
Check the JRE and JAVA path used by your TIBCO Administrator for example :
Changing the environmental variable for JRE and JAVA from 1.5.0 to 1.6.0 directory path will resolve the issue.

Note: If you try to use a class that was compiled for Java 6 or newer on a Java 5 JVM you will see the error: 
"UnsupportedClassVersionError: Bad version number in .class file."