Well then something has updated your copy of communicator.php
Show us line 53 in communicator.php.
If your still running dolphin 7.0.0 then you should see something line this.
'person_switcher' => ( isset($_GET['person_switcher']) ) ? $_GET['person_switcher'] : 'to',
If you see this
'communicator_mode' => ( false !== bx_get('communicator_mode') )
Then your copy has been updated to a version not compatable with the version of dolphin your running.
If thats the case then ask these mod authors or check the mods yourself to see if any of them includes a updated copy of that file.
I have asked who installed the mods and said that it has nothing to do with the communicator
49 // logged member's ID;
50 'member_id' => $iProfileId,
52 // page mode ;
53 'communicator_mode' => ( false !== bx_get('communicator_mode') )
54 ? bx_get('communicator_mode')
55 : '',
57 // switch the person mode - from me or to me ;
58 'person_switcher' => ( false !== bx_get('person_switcher') )
59 ? bx_get('person_switcher')
60 : 'to',
61 // type of message's sort ;
62 'sorting' => ( false !== bx_get('sorting'))
? bx_get('sorting')
: 'date_desc',
// contain number of current page ;
'page' => ( false !== bx_get('page'))
? (int) bx_get('page')
: 1,
// contain per page number for current page ;
'per_page' => ( false !== bx_get('per_page'))
? (int) bx_get('per_page')
: 10,