I have no access to Win2k3 at the moment, but your WinXP should have a command.com.

On my XP here:

D:\temp>perl -e "print grep {-f $_.'/command.com'} split /;/,$ENV{PATH
+}"
C:\WINDOWS\system32
[download]

Microsoft advises to "repair" your XP under such circumstances (KB324767).

But as noted elsewhere in this thread: cmd.exe should be called by IPC::Run. Or even better $ENV{COMSPEC} maybe, which points to the primary "shell" used by an MS-OS since MS-DOS times.