It just returns
ERROR: Unable to create signature file. It doesn't say why... Anyone had this before and found a solution?
I had the same problem and solved it by giving the group name without the @permanent part.
Take a look at the /yourlocation/permanent/group folder. You may find there a "yourgroup" folder and a folder "yourgroup@permanent". So take care when you give parameters to i.gensigset so that when you give the name of group you omit the @permanent.