Error while installing an application to a workspace

We have received the following error a few times out of 40+ installations:
ORA-20001: GET_BLOCK Error. ORA-20001: Execution of the statement was unsuccessful. ORA-00001: unique constraint (FLOWS_010600.WWV_FLOWS_ALIAS_IDX) violated <pre>begin wwv_flow_api.create_flow( p_id =&gt;129, p_display_id=&gt;129, p_owner =&gt; 'MERLINDEV', p_name =&gt; 'Merlin 5.4', p_alias =&gt; 'MERLIN', p_page_view_logging =&gt; 'YES', p_default_page_template=&gt; 13755347070366358 + wwv_flow_api.g_id_offset, p_printer_friendly_template
Background: We have developed a application that is used by multiple clients and as such requires that each client have their own version of the application. This is because each application is connected to the client's schema. Each application has the same application alias but is installed in a unique workspace which makes calling and starting the application via a URL easy, i.e.
When installing the application into a workspace for the first time we allow HTML DB to Auto Assign the application ID.
We have received the above error 3 times out of 40+ installations and when it occurs we simply repeat the install and all goes well. I was wondering if anyone has either seen this, knows what causes it and can suggest a remedy or things to watch out for.

Thanks Scott. I've also been looking for a pattern of consistency that would point to the cause of the problem but have been unable to find one. I was hoping that others may have experienced the same error and could help to shed some light here.
I dug around some and found that the wwv_flows_alias_idx constraint is a unique index on the alias and security_group_id columns of wwv_flows. My application has an alias that is the same for all installations so I thought that somehow a previously used value for security_group_id was being generated causing the unique constraint violation. Can you tell me how that value is generated during the install process? Is it some sort of hashing function?