Dear Alvina,
After looking at your problem, it appears that both of your faults cut the entire domain. In this case, there are no buried edges, and you therefore should not use the edge nodeset in your fault description. This should resolve the topology problem; however, you may still run into problems with your solution due to both faults cutting the entire domain. I know that this was a problem with previous versions of PyLith and I can’t remember if the problem is fixed in the current version or not.
Cheers,
Charles