I'm using Expert Debugger (http://www.ankord.com/) with DBG 2.11.32. Entering "http://localhost/index.php?DBGSESSID=1@clienthost:7869" usually causes DBG to connect to DBG listener and DBGListener starts Expert Debugger. That's the background of what I'm doing.

The problem I'm encountering is sometimes that browser address gives a

"failed to establish connection to client host on 127.0.0.1:7869"

If I use http://localhost/index.php?DBGSESSID=1@192.168.0.31:7869 then everything works just fine.

Now, 192.168.0.31 and 127.0.0.1 are the same computer. Is there are bug in DBG 2.11.32?

when dbg sees "clienthost" keyword in its variable, it resolves it to real host IP with $_SERVER['REMOTE_ADDR'] value. Check if you have at least on of register_long_arrays or register_argc_argv settings enabled.