I had functional and properly licenced (purchased!) Mathematica and Maple installations on my computer, running Kubuntu Dapper. After a certain update (or something), my "HostID"'s in both applications have changed. I have NOT upgraded to Edgy, the computer is still running Dapper.
I got around the problem in Mathematica by actually emailing the company and asking for another password to help me.. However, Maple reports "Missing host ID for licence server", which is something of a problem as I don't even know what to do with it!!
Anybody having the same problem? Why does it happen - it's a very annoying thing, can it somehow be avoided - makes me want not to update my computer... And how can I solve it?