Problems with Symbol Radios and the AS/400

I hope someone on this list can help me.

I have been using Symbol Radios with Spectum24 for over a year on a
wide-area-network with frame-relay lines. I recently converted the network
from frame-relay to a VPN scenario. All of my network connections are
working fine, with the exception of the radios. The radios are using ROI
System's Avalanche products.

Previously when the radios timed out, the user would simply activate the
radio and they would resume their session on the AS/400. Since we have
installed the new network connections, the user pulls the trigger on the
radio after a timeout and gets a "cannot connect" message. The radio appears
to have lost connection with the original job on the 400 and is attempting
to start a new connection -- to which the AS/400 refuses. When I end the
original job the user is given a sign-on screen and can resume their normal
tasks.

The radios work fine until they are set down and allowed to "time-out". Then
they cannot reconnect to their original job on the AS/400. Ending the job
allows the radios to reconnect just fine instantly.

The system worked fine with this configuration on the frame-relay. There are
no abnormal entries in any job log that I can find. I have upgraded the
firmware in the symbol radios, and increased the timeout values on the
radios, but they have not had any noticeable affects on the system.

Thanks in advance,
Patrick