You should never install the QW757 *after* a recent FSDT update, because by doing this, you downgraded the Addon Manager, since the old QW installers haven't been updated to support our new Live Update system. Because of this, you should ALWAYS run the latest FSDT Live Update AFTER you install the QW757, to fix everything back to the latest and correct version.
The issue of the QW757 crashing at start, is caused because, a few years ago, Esellerate changed its own library and SDK, to be compatible with an OS update that happened at that time. This required to make a few small changes to the QW757 Gauges, to be compatible with the new Esellerate library.
However, you can solve the crash on start, if you save a default flight with ANY other airplane than the 757, then switch to the 757 after the sim is loaded. This will allow you to use the 757 with the latest updates from FSDT. If the Gauge code of the airplane were to be updated as well, this wouldn't be required.
We offered QW our support if they wanted our help to update their installer, and to update their Gauge so users won't run into this issues, but they didn't seem interested, I guess they see the 757 as a Legacy product.