PHP 5.3 error "strtr() expects parameter 1 to be string, array given in .../includes/common.inc"

warning: strtr() expects parameter 1 to be string, array given in [...]/includes/common.inc on line 946.

The error occurs on PHP 5.3 when visiting user/registrer

Here's an excerpt from the backtrace:

[16] => Array
        (
            [function] => accountmenu_translated_menu_link_alter
            [args] => Array
                (
                    [0] => Array
                        (
                            [load_functions] => Array
                                (
                                    [1] => user_uid_optional_load
                                )

                            [to_arg_functions] => a:1:{i:1;s:24:"user_uid_optional_to_arg";}
                            [access_callback] => user_view_access
                            [access_arguments] => a:1:{i:0;i:1;}
                            [page_callback] => realname_user_view
                            [page_arguments] => a:1:{i:0;i:1;}
                            [title] => My account
                            [title_callback] => realname_user_page_title
                            [title_arguments] => a:1:{i:0;i:1;}
                            [type] => 6
                            [description] => 
                            [menu_name] => accountmenu
                            [mlid] => 1504
                            [plid] => 0
                            [link_path] => user/%
                            [router_path] => user/%
                            [link_title] => My account
                            [options] => Array
                                (
                                    [alter] => 1
                                    [attributes] => Array
                                        (
                                            [title] => View/edit user account.
                                        )

                                    [accountmenu_link_title] => My account
                                )

                            [module] => accountmenu
                            [hidden] => 0
                            [external] => 0
                            [has_children] => 0
                            [expanded] => 0
                            [weight] => 0
                            [depth] => 1
                            [customized] => 0
                            [p1] => 1504
                            [p2] => 0
                            [p3] => 0
                            [p4] => 0
                            [p5] => 0
                            [p6] => 0
                            [p7] => 0
                            [p8] => 0
                            [p9] => 0
                            [updated] => 0
                            [in_active_trail] => 
                            [href] => user/0
                            [access] => 
                        )

                    [1] => Array
                        (
                            [0] => user
                            [1] => stdClass Object
                                (
                                    [uid] => 0
                                    [name] => 
                                    [pass] => 
                                    [mail] => 
                                    [mode] => 0
                                    [sort] => 0
                                    [threshold] => 0
                                    [theme] => 
                                    [signature] => 
                                    [signature_format] => 0
                                    [created] => 0
                                    [access] => 0
                                    [login] => 0
                                    [status] => 0
                                    [timezone] => 
                                    [language] => 
                                    [picture] => 
                                    [init] => 
                                    [data] => 
                                    [timezone_name] => 
                                    [roles] => Array
                                        (
                                            [1] => anonymous user
                                        )

                                    [realname] => 
                                )

                        )

                )

        )

    [17] => Array
        (
            [file] => [...]/sites/all/modules/accountmenu/accountmenu.module
            [line] => 162
            [function] => t
            [args] => Array
                (
                    [0] => 
                    [1] => Array
                        (
                            [@name] => 
                            [@realname] => 
                            [!name] => 
                            [!realname] => 
                        )

                )

        )

    [18] => Array
        (
            [file] => [...]/includes/common.inc
            [line] => 946
            [function] => strtr
            [args] => Array
                (