Weird,VB.NET MSComm RX error

Hi guys,I've been using Visual Basic 6 for a long time.Recently I've upgraded to Visual Studio .NET,with Visual Basic .NET inside of course.I was getting along pretty well with the MSComm component in VB6,sending and receiving data as I wish.Then I got stuck while tring to receive data in VB.NET.I set a breakpoint at the AxMSComm_OnComm event and monitored those variants involved.On receiving data defined by the "RThreshold" setting of MSComm component,the program entered the breakpoint.And soon I found the value of AxMSComm.InBuffCount was 0 !! This is impossible before anything was read out from the buffer.The data in the input buffer was lost!

I changed the input mode(text/binary),"InputLen" and "RThreshold" settings many times to different combination just to find I was doing it in vain.What am I supposed to do?Remove VB.NET and reinstall the VB6?

U MIGHT GET ANSWER IN THE FOLLOWING LINKS

h**p://welther.nl/hugo/CO%20artikelen/vblab05.zip
h**p://welther.nl/hugo/CO%20artikelen/vblab.zip

Thanks a lot!