Yes there is a way around this, the reason that ESI effectrively switch off when you installed a network, or connected the machine you use ESI on to a network, is that you activated a new IP (Internet Protocol) address for this machine, this is then written to all the startup files on the PC, ESI sees this change & assumes that you are going to try to share this info to other PCs, as you are licenced to run ESI on up to 3 machines, it doesn't like it. You DON'T need to disconnect you network to have ESI running, you simply need to have the system configured as you want it, then go to the menu at the top of the ESI screen, go to 'release' then 'request' then print out that info, fax it to Bosch & they will eventually get a new release code back to you to enable it all to work. Even better, if you're on the net, go to https://www.bosch-esitronic.com and register your code there so as to get a code instantly. Dead easy. (Make sure you use https not http as it is a secure site).
Any problems let me know & I'll guide you.
Hope this helps you,
regards,
Rob Drinkwater. Business Development Manager - CAFTEC Division. Camberley Auto Factors Limited.