site exec c:\winnt\system32\ping
www.google.fr
Makes me think the problem might be with the active directory in your batch file...
at the top of your .bat file, do this:
c:
cd c:\some.dir
replace c: by the right drive
and some.dir by the dir in which your .bat is located.
this will better reproduce the way you execute the .bat from the command prompt...
you could also try from a command prompt:
cd c:\ioftpd\system
c:\some.dir\your.bat
this will simulate the way ioftpd executes your .bat file.