Unable to generate HAR file.

I am trying to spawn a test on my private instance on amazon EC2 with following params:
params = {
‘url’: ‘http://dailymail.co.uk/travel/index.html’,
‘f’: ‘json’,
‘script’: script,
‘runs’: 3,
‘video’: 1,
‘cmdline’: ‘–use-spdy=off’,
‘web10’: 0,
‘fvonly’: 1,
‘mv’: 1,
‘private’: 1,
‘location’: ‘’

script = “akamai pragma headers and navigate http://dailymail.co.uk/travel/index.html

The test spawns properly but after the completion when we try to generate the HAR it gives a 500 error.

Extra Info:
When we tried to debug the php code we traced the problem to following piece of code:
“explode("\t”,str_replace("\t", "\t ", $line))”