WordPress MU

Hi everyone,

How do I fix this error:
http://feedvalidator.org/check.cgi?url=http%3A%2F%2Fwww.options-university.biz%2Fblog%2Ffeed%2F

The error message:
This feed does not validate.

* line 27, column 210: XML parsing error: <unknown>:28:0: unclosed CDATA section

QUESTION:
How do i fix this error?
Which file should I change/modify?

Thanks in advance.
Sincerely,
Tanady

Have you looked at line 27? It's telling you what the problem is.