As I said in a previous post, Beatrix code works OK. Its problem is that before accessing a file a permission is needed and after accessing it has to be released (in Jim’s code: SSB.start and SSB.Stop): something I’m not able to implement.
So I went back to Jim’s code and I found that, in the SSB module > Structures > Range, if you remove “start as int32” and “length as int32”, and replace them with “start as integer” and “length as integer”, everything work all right. I cannot say that that “is” the solution, but at least it works.