The filenames in the UL lists doesn't match MS filenames (or is it the other way?
)WindowsServer2003-KB931836-x86-ENU.exe should be: WindowsServer2003-KB931836-v2-x86-ENU.exe
WindowsServer2003-KB925876-x86-ENU.exe should be: WindowsServer2003-KB925876-v2-x86-ENU.exe
Exchange2003-KB911829-v2-x86-ENU.exe should be: Exchange2003-KB911829-v3-x86-ENU.exe
I changed this in my lists, and it worked like a charm...