Something is wrong with priorities code, Uppaal does not like mixing scalars and priorities. Perhaps some wrong assumptions are made in counting the symmetric processes?
Created attachment 152 [details]
A sample model to demonstrate a disconnect (server segfault)
Uppaal segfaults in a few steps of state exploration with the model attached.
I am not sure if it's the same problem, but the following declaration alone gives segfault:
meta int i;
chan c1, c2, c3;
chan priority c1, c2 < c3;
I looked at the coredump: it seems that system builder gets a reference to i when it tries to access c1, then it tries to evaluate this variable expression on null state and surely segfaults (value of i depends on state, whereas channel value is something else).