This is a system which has been introduced a few months ago.
It works like this:
At the start you can create 10 reports at a time.
After an admin checked your report he evaluates the report. If it's positive you'll be able to do 11 reports at a time, if it's negative you can only do 9 reports at a time.
This system tries to reduce reports from people who abuse the system or often report kickable offences.
So to answer you question: You can only do a max. amount of reports at a time (in your case its 11 reports at a time). When you report 11 people you can do 0 more reports. When a report has been accepted/declined and you got a positive feedback you can create a new report. Hope you understand it :-)