Be sure that your world file has the Datum WGS84 and is in geographic coordinates.
You need an image, which has the same file name as the world file.
example.
mygoegraphicimage.tfw
requires..
mygoegraphicimage.tif (or tiff)
How can I check if this file is geographic or UTM ?
open the world file in a text editor. if the first 2 values are outside of the range -180 to 180 your world file is probably UTM, and without a zone number, it is in not possible to reference.