I\'ve written a WCF service with .NET 4.0, which is hosted on my Windows 7 x64 Ultimate system with IIS 7.5. One of the service methods has an \'object\' as arg
x64
This helped me to resolve the problem (one line - split for readability / copy-ability):
C:\Windows\System32\inetsrv\appcmd set config "YOUR_WEBSITE_NAME" -section:system.webServer/serverRuntime /uploadReadAheadSize:"2147483647" /commit:apphost