Changing windows wallpaper

I'm trying to change windows wallpaper using the following function:
Result = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, strBitmap, 0)
where strBitmap is a full path to new bmp file that user wants to set as wallpaper. No errors what so ever, but no wallpaper change as well. I tried this on Windows 98 and NT. Can anybody tell me what is wrong?
Thanks in advance.

Send me your E-Mail address and i will send you the code that you need, The code works as i've been using it for nearly five years.