BusinessContextServiceException: Activity token "XXXXX" has been terminated   

Hi,
We are running into an unique issue related to BusinessContextServiceException.
We login to the storefront, we create orders and after that we gave wait time of 5 minutes. After completion of 5 minutes when we click on any of the links in storefronts we are getting "BusinessContextServiceException:Activity token "XXXXX" has been terminated".
It is only happening if the wait time is >=5 minutes.
In wcs we have set logintimeout to 4 hours.
In httpd.conf file I am able to see "timeout"set to 300 secs.(this is the default value)
Can this be an issue? Did anyone experience the similar problem before also.
or when this activity token error will be generated.

Thanks
Ravi