About the "network connection error" and maybe other errors when trying to update the firmware:
While experimenting with the firmware I saw the "Radius Programmer Software" establishes a secure connection to www . provapetools . com, (like when you access a secure web page: "https"), it implies the reception of a digital certificate, that in simple words, is used to encrypt the data between the server (provapetools) and the client (Radius Programmer).
Once the secure connection is established, the "Radius Programmer" software sign in the server with a user and password and reads the available firmware updates, etc. etc.
If there is "something" analyzing the connection, or between the two, as for example, a proxy server, there could be errors (as validation of the digital certificate) that would prevent the secure connection between the Radius Programmer and the Provape server (provapetools), ending with a "network connection" error.
As already was suggested, things you can try:
Try the update in another network, for example, at home, or on a public network.
Some companies implement what is known as "Transparent Proxy" (to save bandwidth), or other kind of network data analysis services (to prevent virues on the data transferred, for example), thant could cause problems when validating secure connections / digital certificates.
Ensure there is not a windows firewall rule that prevents the "Radius Programmer" software to connect to the Propave server (you can disable temporarily the windows firewall).
Ensure that your antivirus is not blocking the connection, some antivirus include sort of Internet security protection, you can disable temporarily the antivirus.
Use the supplied USB cable.