I don't know, sorry. I've never used xHarbour.com. What I can say is that xharbour.lib does not exist in the xHarbour repository. Maybe in the new xHarbour Builder folder, I did not check it.
Antonio, you should throw away all the old stuff and get the latest official xHarbour build. There is no problem at all using that build with any C compiler and FWH. I don't know about xHarbour.com, though.