I suspect memory leak in Miranda.
Threads and codes:
Win32' (0x1518) 0 (0x0).
IRC: ConnectServer' (0xce8) 0 (0x0).
Win32' (0x15bc) 1865217 (0x1c7601).
IRC: ResolveIPThread' (0x109c) 16450817 (0xfb0501).
Win32' (0x1220) 16045825 (0xf4d701).
IRC: DisconnectServer' (0xbd8) 0 (0x0).
IRC: CIrcProto' (0x1714) 15495048 (0xec6f88).
Win32' (0x9fc) 0 (0x0).