I get this too on precise with FF 9. I think Peter had at one point said "Open this filetype with Firefox automatically from now on" at one point, because I just get the standard "how do you want to open this downloaded file?" dialog, which defaults to Firefox.
If I open the downloaded jnlp file, it opens a new tab and I just get the same dialog again. So I can confirm the infinite loop nature of this.
I get this too on precise with FF 9. I think Peter had at one point said "Open this filetype with Firefox automatically from now on" at one point, because I just get the standard "how do you want to open this downloaded file?" dialog, which defaults to Firefox.
If I open the downloaded jnlp file, it opens a new tab and I just get the same dialog again. So I can confirm the infinite loop nature of this.