You must modify the code in the CPlugin.h, no in CPluginGUI.h. The line #define PLIK_OKNA "\\OknoDialogowe.glade"
does not exist in the file CPluginGUI.h.lol
Dude, please check the all it again.
Unless otherwise noted, the rights for the individual plugins are with their respective authors. Logo image by Jakub Steiner.