Agree with thanaz, it's shell dependent.

sh -c "echo -e 'hi there'"
  -e hi there
[download]

On some systems. Seems to be when dash (a simpler, faster shell), is used for sh instead of bash.

bash -c "echo -e 'hi there'"
  hi there

/bin/echo -e 'hi there'
  hi there
[download]

But why are you calling echo from perl in the first place? It's not necessary.