cryptic error on launch when .esx files do not exist any more

[filip krzysztof tomaszewski aka zambari]

this is really a ux improvement suggestion rather than a bug

when last open file do not exist any more, the user is greeted with a
rather cryptic error says:
"Cannot open the editor. An unhandled exception was thrown"

when in fact the state is stable and old files can be opened just fine
through File/Open command,

osx mavericks 10.9.5
java version "1.7.0_67"

see attached screenshots
whatever the exception is, it would be nice to handle it displaying an
error message with ' this last opened file does not exist any more '
or similar, seeing the seemingly unrecoverable error message really
threw me off for a minute


cheers