Strange.
Everything works in my setup. With and without TOPCAT. With and without real weather.
I attach screenshots:
https://www.dropbox.com/sh/bg0p1e8he0co0de/y1zlBCoinH
When I use TOPCAT, prepare load, then I'm doing exports. Then send (not save).
P3D2.1 without the hotfix.
Maybe TAT/SAT is wrong?
What you have language in windows? Maybe here is the problem:
http://www.nirvanatec.com/support/regional_sett.htm