The ctrlSetURL command does not work the same way the config attribute url does. The attribute can link to files (and folders):
class Ctrl: RscText { idc = -1; text = "Open"; url = "file:///P:/buldozer.cfg"; x = 0; y = 0; w = 1; h = 1; };
but the command can not:
_ctrl ctrlSetURL "file:///P:/buldozer.cfg"; // does not set the URI