Denise,
This sounds as if it is the way that HSU has set up their enrollment. It may be they have this policy to prevent students from accidentally signing up for something that will cost them more... You will need to talk to their administration or tech support. This is the international site that supports Moodle, but we have no access to the individual sites. You might try your school's website to see if there is a tech support phone number that is open on Sundays.
Paula Clough