It's probably just the case that you did not reboot. ActivePerl may have added the proper line to your AUTOEXEC.BAT file, but DOS windows will not get any of it's benefits until you reboot. You can also see if it is there by looking at the fie yourself. Go to Start->Run and enter WORDPAD C:\AUTOEXEC.BAT. Look for a line that starts with PATH and see if the word PERL is in there. It should be something like C:\PERL\BIN. If it *is* in there, you are all set, just reboot. If not, you will have to add it yourself. Find the directory that ActivePerl was installed into, and then make sure that it has a "BIN" directory under that. This is the directory that actually stores the PERL.EXE file, which is what your DOS windows could not find. (You can also do a "Find" for PERL.EXE to determine the correct directory)

(Side note: you can type the full path to PERL.EXE or set a temporary path at the command line with PATH=%PATH%;C:\PERL\BIN if you do not wish to reboot yet.) At any rate, the paths (places to look for executable files) are separated by semicolons, so just add the path to perl at the end of the final PATH statement in your AUTOEXEC.BAT. In other words, if your AUTOEXEC.BAT looks ike this:

@ECHO OFF
DOSKEY /INSERT
SET TZ=EST5EDT
cls
Echo Depressing kernel...
PATH=C:\WINDOWS;C:\WINDOWS\COMMAND
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just change the last line to read:

PATH=C:\WINDOWS;C:\WINDOWS\COMMAND;C:\PERL\BIN
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(or wherever ActivePerl has installed Perl. If you still can't find it, just do a Find on "PERL.EXE")