RegOpenKeyEx fails on Remote Machine

hallo,
i want to access the registry on a remote machine (a member of my network).
first i try with
RegConnectRegistry(\\Host, HKEY_LOCAL_MACHINE, &hRootKey)
which returns ERROR_SUCCESS.
then, i want to open a key with
RegOpenKeyEx(RootKey,
Subkey,
0,
KEY_ALL_ACCESS,
&Key)
but this returns error code 997

// MessageId: ERROR_IO_PENDING
//
// MessageText:
//
// Overlapped I/O operation is in progress.
//
#define ERROR_IO_PENDING 997L // dderror

why is an error risen? and how can i access the registry on a remote
computer without such a message?
regards
thomas