Hi...I think it could be due to Ethernet media problems which causes either by 1. excessive noise2. excessive collision3. late collisions4. excessive runt frames etc.. Below is the link which might be helpful for troubleshooting:http://www.cisco.com/...

Yap, I'm sure that the IOS version does support 2FE2W module. Seen before in one of my customer site, upgrade the IOS to 12.2 or go to cisco sales tool to check on the min. IOS that supports NM-2FE2W. Below is the link.. ;>http://www.cisco.com/cgi-bi...

1st thing 1st, have you purchased the Enhanced IP License for the L3 module?

Please correct me if I'm wrong... cisco 1601R does not support the VPN module, only cisco 1700 series routers support this VPN module.