The function scorm_eval_prerequisites() uses the evil PHP eval() function. We should convert that to using the evalMath() class already included in Moodle which performs a similar task without being "evil"

the problematic code:
return eval('return '.implode($stack).';');

Most packages I have only have a single prereq item so $stack only contains a single item with the string ' true ' or ' false ' and in this case all that is really needed is:

return $element;

instead of that other crap.

but... if there are multiple items $stack would contain something like this: (I don't have any packages to test this)

Array
(
[0] => false
[1] => true
)
(the code puts 2 spaces before and after each value in the array (' false ', ' true ')