ColdFusion stores those settings in the XML file C:\ColdFusion10\cfusion\lib\neo-runtime.xml. Follow the usual procedure to back up a file before editing it.
Open the file in a text editor. The entry you need to locate looks like this:
<var name='requestLimit'><number>25.0</number></var>
Change the value to 5.0, and restart ColdFusion. Return to the Administrator and verify whether the change has stayed.