Follow-up on this issue... The problem was that an old copy of gdb32.dll was sitting in C:\Windows\SysWOW64. That was loaded before IBAnalyst tried to use fbclient.dll, and it was not suitable. The solution was to copying the recent 32-bit fbclient.dll to gds32.dll in the same folder as IBAnalyst.exe.
There was no mysterious firewall issue whatsoever. Many thanks to Alexey at IBSurgeon for all the off-list emails and remote support to resolve this. Ann
