I think the problem is that your host has upgraded their version of PHP to 5.3 which is known to not work properly in earlier versions of vB (3.8.4 downward).
Contact your host and ask them to downgrade to PHP 5.2.
Code:
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 49
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 101
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 105
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 113
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 124
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 128
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 136
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 205
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/init.php on line 383
Deprecated: Assigning the return value of new by reference is deprecated in /home/-/public_html/forum/includes/class_core.php on line 2552