Check the absolute timeout in the Router and also the uauth timer of the aaa.
It is probable that it is a timer issue. You could increase the timeout values.
The New PIN and Next Tokencode functions, depends on all components in the authentication path. For example, dial-up users must typically use a terminal window after dial-up to gain this full functionality.
I would advise you to check the details of the method of access that would be required to avail the Next token facility...
Also refer:
http://www.cisco.com/en/US/products/sw/secursw/ps2120/products_configuration_guide_chapter09186a00800eb0b5.html