I am having the exact same error using the Siemens USB Module. I thought it was a problem with my old laptop. I contacted IT and they let me borrow another to check the USB Module out. I installed 3.2 SP4 and instantly could conect to the S7-200. IT said fine, we will just transfer your lotus notes, favorites and documents to this new machine. They did and now I can not connect with the USB again. I am having fits trying to figure this out. Any suggestions of what could cause a conflict that would not let me use the Siemens USB PPI module. It does see it in Device Manager.