The solution is provided in Oracle's note 330165.1

Set both time outs beyond the maximum time the application / MS Word is used.

a) Set FORMS_TIMEOUT in the envFile used (e.g. default.env )

b) For the oc4j timeout, edit the web.xml in OracleAS --> j2EE --> OC4J_BI_Forms --> applications --> formsapp -->formsweb --> Web-inf
Add the three lines:

<session-config>
<session-timeout>60</session-timeout>
</session-config>

before the closing tag </web-app>

c) Restart the mid-tier services.

If this does not work then execute the following solution:

Go to the process-type tag with id="OC4J_BI_FORMS" module-id="OC4J".

Under this process-type tag, go to the category tag with the id="urlping-parameters".

Replace the line <data id="/reports/rwservlet/pingserver?start=auto" value="200"/>
with <data id="/forms90/l90servlet" value="200"/>.

Then, under the line <restart timeout="720" retry="2"/>
add: <ping timeout="300" interval="20"/>