There is no Tivoli imposed time limit for your second try, though Sylvan may not be able to download the exam for you until the next day. We do have a policy that is fairly standard in the IT certification industry that states that a person may not take the same exam more than twice in any 30-day period. This means if you fail an exam, try again 10 days later and fail for the second time, you must wait for 20 more days before giving it a third try. I completed the recommended education for a certification test but failed the test. In general, certification tests validate implementation knowledge and skill as defined by the Certification Role description.
Education is only a part of the process to prepare for certification tests.
It is not surprising that those who have little hands-on implementation experience would fail the test. I just took one of the Tivoli Certification tests and was somewhat surprised that I wasn't able to achieve a higher pass mark. I have lots of experience and know the subject as well as any of the people who wrote the questions. The test is not like a school test - more correct does not necessarily indicate more knowledge and more skill as a Tivoli Certified individual. This is the most difficult thing to comprehend about the certification tests.