I have a feeling I did exactly what curbina did stated in his post below.
I already had the new Joomla 1.5.4 installed... I guess when I followed the instructions I just overwrote the existing files? So, I need to delete everything & start over by just uploading the package & running it?
Also, is the InStock 1.5.4 or 1.5.3 and if it is 1.5.3 how do I go about upgrading instock to 1.5.4 without messing up the files?