gsb stacktrace:

#0  0x00b95ffe in xml_string () from /usr/lib/graphviz/libgvc.so.2
#1  0x00b96016 in xml_string () from /usr/lib/graphviz/libgvc.so.2
#2  0x00b96016 in xml_string () from /usr/lib/graphviz/libgvc.so.2
#3  0x00b969da in rank () from /usr/lib/graphviz/libgvc.so.2
#4  0x0012ace8 in dot_rank ()
   from /usr/lib/graphviz/libgvplugin_dot_layout.so.2
#5  0x0012484a in dot_layout ()
   from /usr/lib/graphviz/libgvplugin_dot_layout.so.2
#6  0x00b8176b in gvLayoutJobs () from /usr/lib/graphviz/libgvc.so.2
#7  0x08048bf2 in ?? ()
#8  0x0049ed5f in __libc_start_main () from /lib/libc.so.6
#9  0x08048931 in ?? ()

 digraph G {
 graph [rankdir=BT]
 subgraph title { graph [rank=max]
  9999999 [label = " SITE INDEPENDENT ", shape=box]; };
 0[label = "Root", color = "green"];
 1[label = "ValExpNode", color = "green"];
 1->0 [label = "V",color = "black"];
 }