So i've downloaded the code to have a play around.
Im reasonably new at LAMP etc.. but have figured out most of the problems on my own. The thing is I am getting this on the profile page under balance:

Warning: gmp_cmp(): Unable to convert variable to GMP - wrong type in /var/www/bcx/util.php on line 115

Im guessing GMP or something may not be configured properly? Any ideas?