As Brian says, if you've been trying to profile using the "Attach to process" profiling mode, you may get better results instead by choosing the ".NET executable" application type on Application Settings:
1. In the ".NET executable" field, tell ANTS to profile the IIS worker process (probably something like C:Program Files (x86)IIS Expressiisexpress.exe)
2. In the "Arguments" field, specify the app you want to profile - e.g. /site:"MyCMSSystem"
Does this help at all?