OK. I am going to give you some basic guidance on the steps you should take but if it works (you get to SD4) and then for some reason the theme still doesn't work for you - then you should abandon the idea of installing this theme and just use Raven's or something different because I will not be able to help you due to my business travels.
I don't really understand where you currently stand. But let's start from the base point. First you need to use fastboot to flash the stock 408 recovery, and you can find it here: http://forum.xda-developers.com/wiki/Dell_Venue
While you on that page download the 408 package, rename it to update.pkg and move it to your phone's SD card. (You may already have that there)
After you flash the 408 recovery image in fastboot you need to reboot (fastboot reboot) and when it tries to reboot you need to hold both volume buttons and power button to get to the screen where you are given a choice to install the software update (update sw package). Choose to install the update.pkg and let it load fully. Now you should be on stock Olleh 408 build. DO NOT do a factory reset
Once you have stock Olleh installed and running, you need to install CWM by using the steps explained here: http://forum.xda-developers.com/show....php?t=1423002
Now you should have CWM recovery installed and it is time to flash deodexed 408 ROM which you can find here: http://forum.xda-developers.com/show....php?t=1416537
Let the deodexed ROM fully load. DO NOT do a factory reset.
Now you should have deodexed 408 ROM installed. Final ROM to install would be SD4 2.5.0. Just flash the StreakDroid zip and let it fully load. After it's been fully loaded, you may need to flash Superuser to root your Venue (in case SD4 doesn't come already pre-rooted). DO NOT do a factory reset.
Final step is to flash the theme zip via CWM - again do not do a factory reset
If the theme still doesn't work - i.e. your status bar is messed up or something, just flash SD4 via CWM again and forget about my theme. And again, DO NOT factory reset
. Best of luck and hope it works out.
One more thing: do not factory reset
I am serious.
Google Nexus 5 - 4.4.2 Stock ROM
Dell Venue 8 - 4.4.2 Stock ROM