ubuntu linux 12.04 with custom qt 4.8.5 download
see my contributions to  and :
in a nutshell:
Qt’s getaddrinfo(..) abstraction must be changed to make the lookupHost(..) call really async. right now it is sync, when the network connection between client and DNS server is interrupted, which isn’t that seldom as one might expect.
for a detailed description please see:
also note my comments on the issue in the regard of the same error found by others, links:
-  http://www.qtcentre.org/threads/41649-QNetworkAccessManager-smart-handling-of-timeouts-network-errors
-  https://qt-project.org/forums/viewthread/11763
please feel free to contact me any time. this fix is too complicated for me as it might change the design quite a bit.