Upload with WinInet

I wrote application for uploading large files using WinInet HttpSendRequestEx. It seems to work OK, but after the HttpOpenRequest call the value of Err.LastDLLError is 122 (ERROR_INSUFFICIENT_BUFFER as in winerror.h mentioned; "The data area passed to a system call is too small"). Moreover, then I'm trying to make call to HttpEndRequest it returns false (i guess it's no good).
The most interesting is that uploading actually works but my callback function does not receive INTERNET_STATUS_REQUEST_COMPLETE or INTERNET_STATUS_RESPONSE_RECEIVED (note, that it receives INTERNET_STATUS_SENDING_REQUEST INTERNET_STATUS_REQUEST_SENT). Unfortunately my application should know then all uploaded files have been recieved by server, so I really need to catch INTERNET_STATUS_RESPONSE_RECEIVED.