Update:
After our Network Admin guy went thru a whole lot of trial and error,
sweat and tears, he with some amount of help from Symantec, finally
came up with a "solution"..
Here is what he reported:
1. The NAV Product requires 128 MEG Ram to run. Some of our machines are strapped at 256MB
2. All unneeded features are turned off including all email scanning, network scanning, tamper protection.
3. The product may need an extensive list of exclusions, including VFP folders and file extensions.
4. Some global parameters may not propagate to workstations in push installs.
5. Some earlier versions of the product may require removal of earlier versions for successful install of 10.1.

Thanks all!