It could be something odd about the locale and a dialog font. For dialog layout the font MS Sans Serif point size 8 is used. It may be this is being substituted on that machine for some reason. If you press Winkey + R and type fonts and press enter you should get the fonts window. Is MS Sans Serif listed? If so double click on it. Do you get a very blocky font at larger sizes?
It is obvious from the screenshot that things are not stock from Microsoft though as you have very thin window frames and a shadow on the window frame. What did you use to change these?
The check for updates button has been resized which indicates something resized the internal dialog which is the tab contents, but nothing else which is why you end up with the mess.
I will ask QA to try Chinese installs just in case during the next week, but as of right now I am unaware of any WindowFX dialog sizing issues on any version of Windows. It should work just fine on out of the box installs of Windows. Before originally replying I actually double checked on Windows 8.1 with 100 and 125% dpi to be sure.