As part of my project I had to write my own drivers for a USB device using calls to kernel32.dll. My project is in C# using VS 2008. So far this device has worked without issue on XP, Vista and Win 7. But on POSReady I get the error below, it happens every time I try to call that particular method. All other method calls seem to work. Unable to find an entry point named 'CancelIoEx' in DLL 'kernel32.dll'. All required updates have been run on the machine. The version of kernel32 is 5.1.2600.6293, newer then what's on my XP machine. Any ideas would be greatly appreciated.