As I mention in my book, these are normally swap space problems, but given that you have already tried bouncing the server and increasing the swap space, I guess that you are hitting a restriction on the heap data segment size allowed by your operating system. How that limit is set depends on your operating system. Try running the Oracle maxmem utility. That will tell you how big a data segment can grow, and which limit it would hit first. If that is similar to the size to which your PGA grows before hitting this error, then you have your explanation.

In our production environment, we are having a peculiar problem. We have oracle 805 running on Unix box. System RAM is 10GB. For the last couple of weeks, we are getting ORA 04030 error. We have the back end programming in Pro*c. We get this error only when we try to perform a particular transaction (especially when we try to execute a particular statement), irrespective of the size of the data involved in the transaction. We increased the SGA, PGA, shutdown the server to free up the memory, increased the OS swap space but still we could not solve this problem. I got your mail from one of my friend. If you have a solution for this, please share with us. I shall appreciate their help. Since this is a production environment, we are lagging behind a lot.