Download this file Factory-update aml.zip and open, drag the factory_update_param.aml file to your sdcard with your update.zip file from your firmware package, then shut down and press home key 3-4 seconds then still holding home key press and hold power key until you see the white droid then realease both keys, it will install the basic framework for your tablet then try following this-
Are you on JB 4.1.1? If so and Superuser+root explorer are there using root explorer go to system/apps and look for google_services_framework.apk and press till a menu pops up and choose install, now do the same with Phonesky.apk this should install the playstore.