Why Isn't BootCamp Working on my iMac 2011?

Well, if you read the Bootcamp instructions, you are supposed to know what types of Mac is compatible within it.

Boot Camp requires a Mac with an Intel processor.

• MacBook introduced in 2015 or later
• MacBook Air introduced in 2012 or later
• MacBook Pro introduced in 2012 or later
• Mac mini introduced in 2012 or later
•   
• iMac introduced in 2012 or later1
• iMac Pro (all models)
• Mac Pro introduced in 2013 or later