As an experienced developer, I have dedicated a significant portion of my career to working with Moodle and troubleshooting similar enrolment issues like the one you're experiencing. I have an in-depth understanding of PHP and SQL--essential components in analysing the failure point and performing a fix without causing any harm to your existing data.
In addition to being well-versed in Moodle's underlying technologies, my proficiency extends to HTML and MySQL as well. Therefore, not only will I be able to resolve your current predicament, but also make any necessary database manipulations or HTML tweaks to guarantee seamless addition of participants.
With me on your project, you won't just get expert problem-solving skills; you'll benefit from my holistic approach and respect for deadlines. Because for me, it's not just about fixing bugs; it's about ensuring optimal functionality within established timeframes. Hiring me would mean making room for efficient resolution, skillful execution, and ultimately a more fluid user experience for your Moodle platform. Let's eliminate this roadblock efficiently and get your enrolment process back on track!