windows xp command prompt

[mike henley]

i have installed the activestate perl, python, tcl, and pragmatic
programmer's ruby. when i go to the command prompt on windows xp and
type perl for example... (or python, ruby... etc) i get the following
message.

'perl' is not recognized as an internal or external command,
operable program or batch file.

in the control panel| system | advanced | environment variables | Path
i have

C:\ruby\bin;C:\Python22;C:\Perl\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem

does anyone know what i should do to fix this problem? (apart from the
obvious of restarting the machine)