Another quick fix for ultimatebb.php (UBB Accelerator). At least PHP 7.3 (Release Candidate)/Debian 10 require this additional modification:
Replace:
function figurelocation ($arg) {
with:
function figurelocation ($arg = "") {
I did my previous testing on PHP 7.0/Debian 9, so this change may be even necessary for PHP 7.1 or PHP 7.2.