If uploading a file you receive an error message 'Entity is too large', here is the solution.
From a command prompt, type:
appcmd.exe set config "PoolCar" -section:system.webServer/serverRuntime /uploadReadAheadSize:"1048576" /commit:apphost
..where "PoolCar" is the name of the web site as you have it configured in IIS. Open IIS and look for the PoolCar node in the sites tree (keep the quotes, just change the site name value if yours is not PoolCar).