Try this translation:

* I'm not sure about types SESSION_TYPE and SESSION_MODE in your code --
* probably DWORD or UINT is Ok for them?
DECLARE INTEGER ACeNetConnect IN ACENET;
	INTEGER @ hObject,;
	STRING    StationName,;
	STRING    UsrID,;
	STRING    Pwd,;
	INTEGER   ConnectionType,;
	INTEGER   SessionMode,;
	STRING    SessionName

DECLARE INTEGER ACeNetDisconnect IN ACENET INTEGER @hObject

DECLARE INTEGER ACeNetPostRequest IN ACENET;
	INTEGER   hObject,;
	STRING    SendBuffer,;
	INTEGER   SendBufferLength,;
	SHORT     SendOptions,;
	STRING    ReceiveBuffer,;
	INTEGER @ ReceiveBufferLength,;
	INTEGER   Tmeout,;
	SHORT   @ ReceiveOptions

DECLARE ACeNetGetErrorText IN ACENET;
	INTEGER ErrorCode,;
	STRING  ErrorText

LOCAL BuffLen, RcvOptions
STORE 0 TO BuffLen, RcvOptions
Ret = ACeNetPostRequest(Handle, SendBuff, SendBuffLen, DATA_ONLY,;
	cBuffer, @BuffLen, 20, @RcvOptions)

Note that parameters ReceiveBufferLength and ReceiveOptions are passed by reference. That means (1) they have to be allocated before calling ACeNetPostRequest function; (2) @ prefix should be applied -- similar to ByRef in VB.