Can anyone tell me why I am getting this error?

Failed to map remote file for
C:\Program Files\PHP\includes\adodb\drivers\adodb-mysql.inc.php
to any local file

I get the same error for C:\Program Files\PHP\includes\adodb\adodb.inc.php

I don't have a problem running ADOdb through the debugger, I just keep getting these stupid errors for each page!

C:\Program Files\PHP\includes is in my include_path in my php.ini file, and PHP is finding the library just fine.

I have version 3.3.3

Is this directory a project's subdirectory or out of the project tree?
In first case everything should work fine.

In latter case, you'll have to put it inside the project tree. Let me show you how:
Suppose you have c:\mywork\project as a project root directory and c:\mywork\includes as a directory where the libraries are, and http://localhost/ corresponds to the directory root and is entered as root url.
In this case you'd do the following:
-change the project root to c:\mywork
-clear root URL
-switch to the MAPPING tab and add just one line with
URL = http://localhost/
local and remote directories = c:\mywork\myproj

the same way you can configure your project if it works with remote web.

that's all tricks.

Well, I want to keep library packages in the PHP\includes directory to separate it from my stuff. This is the way I want to implement it in production. It works fine outside of PHPEd.

So, is it that the debugger is not able to interrogate the php.ini include_path when looking for include'd and/or require'd files and pass that info to PHPEd?
Or what???

Debugger consists of two sides - server and client. The server side works it does so on your remote server and knows nothing about your client side. For example server part may step on your file say /var/www/somedir/myfile.php. When client part receives the server's packet it need to know what local file corresponds to /var/www/somedir/myfile.php and therefore it needs a lookup table to map /var/www/somedir/myfile.php to say c:\myproj\somedir\myfile.php. Strictly speacking, it's not necessary to map all the files, it's sufficient to map only directories. With the mentioned scenario you'd need an entry in the mapping table with
c:\myproj\somedir\ corresponding to /var/www/somedir/
or better
c:\myproj\ corresponding to /var/www/
In latter case all files in /var/www/ will be mapped to c:\myproj\, including ones in somedir subdirectory.
When you create your project and set Project Root directory to say c:\myproj\ and set remote root directory to /var/www/, phped creates one mappig entry for you automatically.

With the given example if for whatsoever reason, some of the files are not in /var/www/ directory, you have to create mapping entry yourself and point phped out where to find the local files. For example, if some files are in /var/inc/ and corresponding copies of the files are available on the local drive c: in c:\php\include\ directory, you'd create mapping entry for them:
/var/inc/ -> c:\php\include\


You may wonder what "URL" column is intended for in the mapping table. The answer is raither simple. PHPED when you run a file, need URL to do so. For example with the given example, if your project root url is
http:\\myhost\, and you opened and run c:\myproj\somedir\somefile.php, phped will run http://myhost/somedir/somefile.php and it's up to your web server to run /var/www/somedir/somefile.php.

So, that means that anything usually sitting in a systems PHP directory like PEAR will be unmapped?

I got around it by disabling "Show mapping errors"

Not. It only means that you have to add mapping entries for such directories.