There are many Notes on Metalink that refer to your problem. Below is just one:

Problem Description:
====================

You have just installed Oracle 8.1.5. You are not using java and set the
JAVA_POOL_SIZE = 0 in the init.ora. On startup you get the following error:

ORA-01078: failure in processing initialization parameters
Cause: A failure occurred during processing of the initialization
parameters during system startup.
Action: Refer to the diagnostic information in the accompanying message
stack and take appropriate action.


Solution Description:
=====================

Set the JAVA_POOL_SIZE to a value greater than or equal to 1MB.


Explanation:
============

In 8.1.5 the minimum setting for the java_pool_size is 1MB due to a bug.
In 8.1.6, you can set the java_pool_size to 0, but 32768 will show up in a
SHOW PARAMETER command.