It won't accept the zip code for Prague for college

Prague, Czech Republic? Did you select that the address was for the school was a Foreign Address? If so, try entering the Postal Code as a just a series of numbers without the space.

The school may not be allowed for credit.  From the IRS:

Eligible educational institution.   An eligible educational institution is generally any accredited public, nonprofit, or proprietary (privately owned profit-making) college, university, vocational school, or other postsecondary educational institution. Also, the institution must be eligible to participate in a student aid program administered by the U.S. Department of Education. Virtually all accredited postsecondary institutions meet this definition.

   An eligible educational institution also includes certain educational institutions located outside the United States that are eligible to participate in a student aid program administered by the U.S. Department of Education.

Is this school eligible for Federal student aid programs?