I am receiving this error whenever I try to install Laravel Artisan Migrations. I'll tell you what I have done...
I have gone into my .bash_profile:
export PATH=/opt/local/bin:/opt/local/sbin:/Applications/MAMP/Library/bin/:/Applications/MAMP/bin/php/php5.5.3/bin:$PATH
and when I check to see which version of PHP I am using, it's the one in my MAMP folder. And it is certainly enabled! But when I type Laravel Artisan: Migrate: Install it prompts me back with MCrypt PHP extension required. Composer is functioning properly. So is Laravel 4. It's this Migrations that is giving me trouble.