SQL & PL/SQL

Hello Justin,
I following is the issue that I am trying to resolve.
I have database A and database B. There is a database link from A to B. I have a function on A that calls a function on B. Function in B calls portal.srw.run_report which run the report and return back a URL. The URL is passed back to A, which is passed back to the calling environment. The URL is then run in a browser. The function in A is called by oracle html application and a .Net web application.

When the function in A is called by the oracle html application the URL takes approximately 526 seconds to be returned the first time and the subsequent attempts take less than a second. But on the other hand, when the function in A is called by the .Net application the first time, I receive the following error.

ORA-02068: following severe error from XXXX
ORA-03113: end-of-file on communication channel

The second request may take approximately 526 seconds and the subsequent requests take less than a sec. I also receive the error if I do a select on a table in B.

When the two environments use the same function call, why is there a difference in the way they are handled?

I was researching about the error online and came across the following link which discussed about checksum and possibly a firewall issue.

http://www.dbasupport.com/forums/archive/index.php/t-41245.html

I would really appreciate it if you can provide an explanation to this issue.