You can fail the PMP exam up to 3 times in one year. When you fail for the third time, you need to wait until the end of the year to re-apply for PMP
For example, let's say you applied for PMP on August 20th, 2010 and your application got accepted. You failed the first time in September, your re-took the test in October and you failed, and then your retook it in December and you failed again. Now you have to wait until August 20th, 2011 to re-apply again. I think when you fail for 3 times and your re-apply then your application might be under scrutiny.