I could flash the ARM translation but not the gapps, using https://stackoverflow.com/a/20013322/98057. I got the 'Ooops, something went wrong while flashing gapps-jb-20121011-signed.zip' error mentioned above. If you read the Genymotion logs and find an entry like:
Sep 16 23:00:02 [Genymotion Player] [Error] [Adb][shell] Unable to finished process: "Process operation timed out"
Try to apply the flash using adbdirectly:
$ adb -s 192.168.56.101:5555 shell "/system/bin/check-archive.sh /sdcard/Download/gapps-jb-20121011-signed.zip"
$ adb -s 192.168.56.101:5555 shell "/system/bin/flash-archive.sh /sdcard/Download/gapps-jb-20121011-signed.zip"
$ adb reboot
Change these commands according to what your log files say (the path and IP will probably be different).
I found the Genymobile log files in the following folder, by the way:
~/.Genymobile/Genymotion/deployed//genymotion-player.log
