I don't think it's wise to post that link - it contains some kind of ID, I suppose your ID... and I'm not sure what it could be used for.
As for the alert itself - I believe the information is returned from the ID company, i.e. it's certainly not avast! trying to scare you. On the other hand, there might be a bug somewhere of course (e.g. the first report always being considered as changed, i.e. raising the alert). No idea, I don't really know much about how it works internally.
