OT: Lost VPN connection

I know this isn't specific to this ng, but I swear I've tried many other
avenues, including the vpn ng's and Netgear directly, but I've received no
replies from any source. This ng is frequented by some very experienced
network folks, so I'm hoping to find some suggestions. Here's the problem:

We have a Netgear FVS328 router/vpn appliance. Two telecommuters work from
home offices and use the Netgear vpn client to connect to our
file/application server. Everything has been working fine until last week
when we changed ISPs. They assigned us a different WAN-side static IP
address, which I entered into the Netgear router. I then entered the new IP
address and subnet mask into the appropriate fields in the ProSafe VPN
software client on the one remote laptop that currently was in the office.
The person took that laptop home and logged in fine.

The next day, however, the remote worker from our office in another town
called me and said she could not log in. At first I assumed she simply had
not updated her client with the new IP settings, but after taking control of
her desktop I discovered that she had been emailed the backup settings file
from the worker whose laptop was manually configured (and working), which
had apparently updated her settings, but she could not connect. When I
checked the log file generated by the client, I saw the following error:
"Error validating the proxy ID." I have triple-checked all of the settings,
and they appear to be identical to the working computer, but I cannot fix
the problem.

Again, the only thing that changed on the host end was the WAN IP address,
which is matched now in the client. But a connection cannot be established.

Input appreciated. And if I've left out critical info, please let me know
and I will be glad to fill in the blanks.

thank you,

jm