compiling problem / Qt DLL files

Hi,

I have a program that handles image files. It can open and use all the image files that Qt4 supports. I recently tried to run my compiled program on another computer and got these errors:

MINGWM10.DLL missing
QTCORE4.DLL missing
QTGUI.DLL missing

I found these files (instead of QTGUI.DLL I found QTGUI4.DLL) in my original computer and transferred them to the other computer that gave the error messages. Now my program started to work on the new computer but I still had one problem. The program can now only handle BMP images but no other image file (for example no JPG's). Looks like I still miss an essential Qt file (perhaps a DLL) that contains info for other image files. The problem is that when I copied all the Qt DLL files I could find, the program could still only handle BMP's. Does anyone know what file I am missing?
Thanks a bunch!