Installing onto an external harddrive
What about if you install it onto your internal hard drive then copy the app across?
The only reason I can think it may not be working is because the GW2 app doesn’t JUST use data from inside the .app to run, it relies on information stored in Application Support to run and it’s possible that it simply doesn’t know how to handle the paths when it’s on an external HD. – Cider (and Wine) sort of spoofs itself into believing that a certain part of your hard drive is the C: drive that it would use on Windows, so yeah maybe that screws something up :S?
I installed to an external firewire drive (only solution for my ageing MBP)… works fine!