As I remeber correct, last time I helped you to static link libstd the version was 5. I guess that on the 64bit systems there is issues with this old version of the library even if it is static linked. If cygwin cross compiler can be updated somehow to use libstd++.6 maybe it will work. However if you already do this(as you mentioned) try to send dinamic linked version of the bots to this guys to see if work. If does we will have to think something, if not the issue is somewhere else and we will have to think again.
