there are several guis for blitz3d, some even use the windowns GUI elements, as Winblitz3d (or similar), see toolbox.
FOr the filelesector you should use the code from the code archives, maybe in "userlibs" or in "file io" sections of the code archives.
A reason why a program works on your machine and not on others could be, it is using a DLL that is located in your "userlibs" folder. While this works on your machine, the folder will be missing on other pcs. solution, provide the DLL in your EXEs folder, instead of the userlibs folder.
FOr the filelesector you should use the code from the code archives, maybe in "userlibs" or in "file io" sections of the code archives.
A reason why a program works on your machine and not on others could be, it is using a DLL that is located in your "userlibs" folder. While this works on your machine, the folder will be missing on other pcs. solution, provide the DLL in your EXEs folder, instead of the userlibs folder.