ARM Translation is basically adding support to run apps compiled for ARM cpus. Most mobile devices use ARM cpus, but Genymotion runs on your laptop which is using a x86(Intel/AMD) cpu. Basically, ARM apps can't run directly on x86 cpus so you have to add software that will emulate an ARM cpu environment, that's ARM Translation. Instagram doesn't support x86 cpus(lazy devs) so you'll have to add ARM Translation support to your Genymotion VM. To do so, install the Android SDK from the Android Developer site, and then follow my guide here:
http://forum.xda-developers.com/showthread.php?t=2528952ARM Translation isn't a magic bullet though. It's not perfect so you will run into apps that will be buggy or flat out crash. Since the ARM Translation software is made by Intel, we can't make improvements or fix bugs ourselves, so we're stuck waiting for new builds to leak out when a new x86 Android device is released with it(not many). Also computers powered by AMD cpus have been found to cause more problems in apps because the ARM Translation is made by Intel and optimized for their cpus.