undefined index warning in PHP for LDAP attribute / associative array?
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I am having trouble retrieving some data out of an LDAP attribute in PHP.

I connect to LDAP, perform my query, and store the results in a var like so: 

`$info = ldap_get_entries($connect, $sr);`


Now, I can store most of the LDAP attributes I need in sessions vars, like so: 


            $_SESSION['accountFirstName'] = $info[0]['givenname'][0];
            $_SESSION['accountLastName'] = $info[0]['sn'][0];
            $_SESSION['accountEmail'] = $info[0]['mail'][0];

These work fine.. No problems. However, there is another var I need to store. I believe It is an associative array. For some reason, no matter what I do, I am getting an `NOTICE: Undefined index` warning for that specific attribute. I have tried storing it like the above demonstration, but to be honest I'm not entirely sure what the [0] indices on either ends of the attribute name mean.. I'm not familiar with LDAP and frankly the setup is very confusing. 


So I guess my questions are: 

 - how do you access associative arrays that are returned from an LDAP
   query?  

 - what does 'undefined index' mean? Does it mean that that
   attribute does not exist, or it does not exist at the index provided?
   
 - How can I test my LDAP query to see if the variable even exists? 
   
 - There is a possibility that the account performing the query does not
   have adequate LDAP access privileges (the project is for a university
   and there is a lot of red tape). Is there any way for me to verify
   that through code?

Thank you! And my apologies for the vagueness of the information provided, I can't be too open-mouthed right now.