Python code error on browser.

[adi.6194]

I have this code which works fine when i run it through terminal. But when i get to the link via browser, it gives me an error:

sh: hdfs: command not found

#!/usr/bin/python

import cgi
import cgitb
import os
import commands

cgitb.enable()

print "content-type:text/html"
print ""

print "--html--"
a=commands.getstatusoutput("hdfs dfs -ls -R /")
print a[1]

Can someone tell me why this is happening?
Output on terminal: