Client access session dropping when going through a router

I am accessing an iseries via the internet. I use client access 5.2 and
windows XP. I am connected via a Linksys router and a Westell DSL modem.
When I connect to the iseries just using the DSL modem, I have no problem.
When I try to connect using the router, the session drops. The error I get
is as follows:

 

CPF5140    Diagnostic    70   04/12/05  13:03:59.324296  QWSGET       QSYS
3240     QUICMENU    QSYS  

                                     Message . . . . :   Session stopped by
a request from device TOWERC1.             

                                     Cause . . . . . :   The request
shutdown was caused by either the user turning    

                                       the power off, by a device error, or
the ASCII controller inactivity timer      

                                       expired. Recovery  . . . :   Close
the files and vary the device off (VRYCFG    

                                       command). If the problem occurs
again, enter the ANZPRB command to run          

                                       problem analysis.


 

Can anyone point me in the right direction.

 

Thanks