Some info to help people debug this:
I have attached the logo file, x2go.xpm
It was introduced on 2012-01-11 as part of a patch file in this commit: http://code.x2go.org/gitweb?p=nx-libs.git;a=commitdiff;h=405bc8f259f230947e5...
That patch file has since been renamed 2 times, but it the logo has never changed.
It is displayed by nx-X11/programs/Xserver/hw/nxagent/Display.c : http://code.x2go.org/gitweb?p=nx-libs.git;a=blob;f=nx-X11/programs/Xserver/h...
which we apply the aforementioned patch to: http://code.x2go.org/gitweb?p=nx-libs.git;a=blob;f=debian/patches/0201_nxage...
-Mike#2