Writing to registry

I am trying to write to the registry. I can create a key, but not a value. can someone tell me what is wrong with this code?

Code:

---

                HKEY hkey;
                DWORD dmDisposition;
               
                RegCreateKeyEx( HKEY_LOCAL_MACHINE, TEXT("Software\\My Company\\My App"), 0, 0, 0, 0, 0, &hkey, &dmDisposition );

                DWORD dwType, cbData;
                BYTE m_dwMaxFileSize;

                dwType = REG_SZ;
                cbData = sizeof(REG_SZ);

                RegSetValueEx( hkey, TEXT("MaxFileSize"), 0, dwType, (PBYTE)"hi", cbData );
       
                RegCloseKey(hkey);

---

Check out the attached cpp/h files.

thx works great :)