While following the instructions on how to update my hardware key for Archicad 17, I got a Java security warning saying that the CodeMeterTrigger software had an unusual mix of "signed and unsigned code", and that it might be dangerous to proceed. So, I clicked the BLOCK button, backed out and checked this forum - but I didn't find anyone else mentioning it.
However I did find the solution, so if anyone DOES have this problem, here's what I found:
Apparently the web-based Java version is "old" (despite being mentioned in the installation guide?) and you can download a hardware key updater from:
http://www.graphisoft.com/downloads/licensing/This worked for me - and the fact that the only Windows option is a 32 bit version didn't stop it working on my 64 bit (Windows 7) computer.