Why do I get these error messages?

[eluser]suntrop[/eluser]
Hi.
I am wondering what this error messages mean:

Code:

ERROR - 2011-07-19 17:55:14 --&gt; Severity: Warning  --&gt; include_once(application/core/MY_Acl.php) [<a href='function.include-once'>function.include-once</a>]: failed to open stream: No such file or directory /path/application/config/config.php 374
ERROR - 2011-07-19 17:55:14 --&gt; Severity: Warning  --&gt; include_once() [<a href='function.include'>function.include</a>]: Failed opening 'application/core/MY_Acl.php' for inclusion (include_path='application//libraries/:.:/usr/local/lib/php') /path/application/config/config.php 374
ERROR - 2011-07-19 17:55:14 --&gt; Severity: Warning  --&gt; include_once(application/core/MY_User_lib.php) [<a href='function.include-once'>function.include-once</a>]: failed to open stream: No such file or directory /path/application/config/config.php 374
ERROR - 2011-07-19 17:55:14 --&gt; Severity: Warning  --&gt; include_once() [<a href='function.include'>function.include</a>]: Failed opening 'application/core/MY_User_lib.php' for inclusion (include_path='application//libraries/:.:/usr/local/lib/php') /path/application/config/config.php 374

I don't know why those two files are "missing". I use them and both work fine. How can I check where this error occurs?

[eluser]suntrop[/eluser]
I think I have found a solution. The Auto-Load function by Phil Sturgeon was an old one. I updated it.

http://ellislab.com/forums/viewthread/191094/#902266