Thank you!!! I wish I could have used this weeks ago, it would have saved me weeks. It might be worth listing a URL of a specific .iso of ubuntu on which it has been tested, as for example there is some problem with debian stable (but not testing) that when used inside a VM makes xschem not work.
BTW There may be some advantage in using this fork of gaw:
https://github.com/StefanSchippers/xschem-gaw