I just saw this morning that the debugger/server/i386 directory of my phpEd 4.5 still contains the 2.18.5 versions while i686 has 2.20.1 versions.
I noticed that because the IDE requires 2.20.1 and complained about it, but I have been using the i386 versions for ages.
Weren't the files updated on my install, or are they just not updated/supported anymore?
Anyway, I installed the 686 version and it works for me, just wanted to "share" the info.

PhpED v 4.5 does not contain debugger/server/i386.
It's left from the previous version you installed before.
If you need modules for win32, you can find them in debugger\server\Win32\i686\

This post helped me as well - just updated to 4.5 and had the same debugger error.

Replaced the php debugger extension with the 686 version for php 5.0.4 - restarted phped and all is working.
Verify the extension name in your php.ini and which php.ini phped is using.

it's a joke then?
phped v4.5 comes with php 5.1.2, not 5.0.4

I prefer to use my already installed version of PHP and php.ini - which is 5.0.4

sure I understood it
but it looks appropriate that PhpED wont' affect it?

Not sure -- all I know is I've been working fine for months and just upgraded. As soon as I tried to use the debugbreak() function, I got the miss-matched debugger version error.

BTW: I really like the IE Toolbar feature now to launch the debugger and profiler.

I think it still works fine but your own php installation which needs new debugger module.
Please proceed with these intructions:
http://forum.nusphere.com/howto-install-debugger-module-t576.html