Quick dirty bugfix (fedanet 0.0.51)

Tarball for version 0.0.51 is downloadable . This is a fix for a couple of bugs (thanks to those who reported them) and an attempt to address one known but hard-to-reproduce protocol flaw. I have to admit it is still buggy, and yes, I know it . Only it may be better than the previous version. Please update, and sorry for the inconvenience.