IT Process Automation

I am trying to write a ValueMap from HTTP object into a ValueMap variable that I defined(Var_2). The snippet below causes the error "msg.valuemap.no.indexed.access". I'm sure I am missing something obvious but can't place it.

length = Process.HTTP_Post_2.HTTPResponseHeaders.length;
for(i=0; i < length; i++)
{
  Process.Var_2.size++
  Process.Var_2[i].Key = Process.HTTP_Post_2.HTTPResponseHeaders[i].key
  Process.Var_2[i].Value = Process.HTTP_Post_2.HTTPResponseHeaders[i].value
}

If I alter the highlighted to Process.Var_2.Key Var_2 the result is better - the last Key/Value pair of HTTPResponseHeaders is stored in Var_2. Trying to figure out how to get all three key/value pairs.

Thanks in advance for any pointers!

You are trying to write out to an array of valuemaps.  Are you sure Var_2 has the "array" option checked?

Many Thanks!