Yes, that does look suspect, doesn't it. As things stand, I can't think of anything other than the portable Arduino install, as it would put all the stuff saved in the arduino15 folder in a subfolder of the install, rather than under 'C:\Documents and Settings\uzivatel\Local Settings\Data aplikacĂ'.
I can't decent guide to link here, but maybe the steps 1 and 3 of this instructable may be of use as a reference :
http://www.instructables.com/id/Portable-installation-guide-of-Arduino-IDE-v165-fo/Basically:
1) Download the "Windows: ZIP file for non admin install" from
https://www.arduino.cc/en/Main/Software2) Right click on the downloaded zip file, and choose "Extact All...", and follow the wizard prompts.
3) You should then have an open folder that contains arduino-1.6.7 (if you download 1.6.7). open that folder
4) In the folder that has 'dist', 'drivers', 'examples', etc, create a folder called 'portable'.
5) Run that downloaded copy of the Arduinio IDE by double-clicking on the arduino.exe icon in that folder.
6) Add '
http://digistump.com/package_digistump_index.json' to the 'Additional board manager URLs' preferences section, and install the Oak core again via the Boards Manager
7) Once that is done, see if you can compile even an empty sketch (with just setup and loop) without any errors. If so, it should work from then onwards!

You can move that 'arduino-1.6.7' folder anywhere you want to - it is a completely self-contained copy of the Arduino IDE, suitable for copying onto a flash drive, etc so you can take it anyware!
Hope that helps.