Alrighty Erik, I took a second look. Sadly I can't walk the same trail 'cause a few things bug me early on. Without worrying about relativity at all, I can see the thing is in error based on units alone. In short, you can't add things like energy to dimensionless numbers, can't multiply by time factor where ever you want, etc. That said, we really can't call the right-hand equation "energy" anymore either, and it keeps crumbling from there.
To meet you in the middle someplace, I dressed up a bitmap to sketch what a "proper" version of this calculation might look like. I had to introduce two unknown variables to walk a similar path to what you did, and the bottom line of the calculation states what the restriction on the unknowns need to be. Mind you this isn't trying to break new ground, I'm trying to rescue your equations from error.
Pretend though that this was all correct out of the gates. Without any math, what are you actually saying with this result?
EDIT: note the factor "gamma" is actually inverted below, changes nothing overall
EDIT2: the final answer is also inverted. just imagine 1 divided by the final result. thats what i get for working with paint.