Parameter 2 to gdriving_gmap() expected to be a reference, value given

This results because of a call from "call_user_func_array()" which has this note:

http://php.net/manual/en/function.call-user-func-array.php
Note: Referenced variables in param_arr are passed to the function by a reference, others are passed by a value. In other words, it does not depend on the function signature whether the parameter is passed by a value or by a reference.

The error doesn't get picked up in PHP before 5.3 even though it is there so you don't see it - I just happen to have php 5.3. Below is the stack trace that shows how the call originates:

Parameter 2 to gdriving_gmap() expected to be a reference, value given
Xdebug: user triggered in /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/common.inc on line 661

Call Stack:
0.0001 648848 1. {main}() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/index.php:0
0.1985 30843800 2. menu_execute_active_handler() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/index.php:20
0.2017 30994544 3. call_user_func_array() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/menu.inc:348
0.2017 30994792 4. dblog_overview() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/menu.inc:0
0.2150 32397664 5. drupal_get_form() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/modules/dblog/dblog.admin.inc:54
0.2155 32407664 6. drupal_prepare_form() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/form.inc:105
0.2155 32411448 7. _element_info() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/form.inc:518
0.2200 32761328 8. module_invoke() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/form.inc:1361
0.2200 32761832 9. call_user_func_array() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/module.inc:462
0.2201 32762080 10. gmap_elements() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/module.inc:0
0.2201 32762392 11. gmap_defaults() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/sites/fixitkeepit.com/modules/gmap/gmap.module:538
0.2201 32769136 12. module_invoke_all() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/sites/fixitkeepit.com/modules/gmap/gmap.module:50
0.2205 32771128 13. call_user_func_array() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/module.inc:483
0.2205 32773152 14. drupal_error_handler() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/module.inc:0
0.2205 32817552 15. xdebug_print_function_stack() /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/common.inc:661

in /srv/www/vhosts/dev/reg/m/multi-001/www/cms/includes/module.inc on line 483.

Since you modify this variable I am not actually sure of the solution at this point.