Need help with Garmin 196 data transfer (long)

I have owned a Garmin 196 for several years and have succesfully
upgraded the system software and the aviation database a number of
times. The newly available obstacle database piqued my interest and I
attempted to upgrade my system software which is required for the
obstacle database.

I was unable to complete this process. My first step was to attempt
to download my routes and waypoints to Mapsource to preserve them. My
computer would recognize the gps and I could begin the download
process. After about 10 seconds I would get a message informing me
that the gps was not detected and suggesting that I check my transfer
protocols, make sure the gps is turned on and something else that I
cannot remember but was irrelevant. I tried this procedure on a
second computer that I have which has also been successfully used in
this manner before.

My gps has the beta system software V3.92 (I think that's the correct
number). The only change that has been made to either computer since
the last succesfull system upgrade is the installation of Norton
Antivirus 2005. I disabled the autoprotect feature, which did not
help.

Here are my questions. Has anyone who is running the beta software
trried to upgrade to the new 4.0? Has anyone had any data transfer
issues with the beta software? This software works fine in every
other respect so I don't have any reason to believe that it is the
culprit here, but I'm not prepared to rule it out. I don't have an
alternate data cable to try, but I would be very surprised if the
cable is bad. It seems well constructed and I can find continuity
through the four pins that connect to the gps. Could Norton be the
problem somehow? I know that Mapsource isn't the problem because I
tried to go to the Garmin site and upgrade the system without saving
my routes and waypoints and it failed in the same manner.

I would greatly appreciate any help that anyone be able to offer. I
have emailed Garmin tech support (last week) but have not heard from
them yet. Thanks.
Rich Russell