I've recently upgraded to PhpED v.4 and my remote debugging sessions no longer work.
Here's the error message:

DBG
Failed to run DBG session
reason:
debugger module version mismatch. Client expects version 2.18, installed module version 2.16
debugger request found in "query_string".

I don't see 2.18 available - is this an error?
Client: Win2K
Servers: Red Hat Linux 9.0 / Apache 2
Can't debug on Windows locahost either.
For the heck of it, I tried changing DBG Listener IDE COM class to PhpED IDE ver 3.3 with a restart and no luck.

My bad... I found v.2.18 in the installation directory (...\debugger\server), uploaded it to my Linux server, restarted Apache and I'm all set.