Okay the error code 0022 is GPU error due to GPU overheating or bad conection (funny enough it seems nearly every common code is gpu related) or can also be triggered by the TSOP so unless you pulled the stickers off with a heat gun and applied them to wax paper then your out of warranty so here are a few tricks that may help.http://www.youtube.com/watch?v=gXPGovugs3M&feature=related
At about 6:58 Lawdawg applies 4 small cuts of credit card to the corners of the gpu chipset with superglue I personally havent tried it but if you have nothing to loose this will even out the pressure on the solder so you can do this while the heatsink is off then tighten the heatsink down ontop of it while the solder is still hot.
If it's not the GPU then you can try Flashing the TSOP if you have a mod chip here's a tutorial.http://www.xbox-scene.com/articles/tsop.php
if none of that works then absolutly must reflow the xbox. Hope it helps. Happy gaming