Smartoptimizer 'stat failed for config.php'

Hi,
I've installed smartoptimizer and at the end of .htaccess :
<IfModule mod_expires.c>
<FilesMatch "\.(gif|jpg|jpeg|png|swf|css|js|html?|xml|txt|ico)$">
ExpiresActive On
ExpiresDefault "access plus 10 years"
</FilesMatch>
</IfModule>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*\.(js|css))$ assets/components/smartoptimizer/connector.php?$1
<IfModule mod_expires.c>
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^(.*\.(js|css|html?|xml|txt))$ assets/components/smartoptimizer/connector.php?$1
</IfModule>
<IfModule !mod_expires.c>
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^(.*\.(gif|jpg|jpeg|png|swf|css|js|html?|xml|txt|ico))$ assets/components/smartoptimizer/connector.php?$1
</IfModule>
</IfModule>
<FilesMatch "\.(gif|jpg|jpeg|png|swf|css|js|html?|xml|txt|ico)$">
FileETag none
</FilesMatch>

No I am getting this on the error.log:

[2012-01-17 09:03:08] (ERROR @[directory]/connector.php : 124) PHP warning: filemtime() [<a href='function.filemtime'>function.filemtime</a>]: stat failed for index.php
[2012-01-17 09:03:08] (ERROR @ [directory]/connector.php : 124) PHP warning: filemtime() [<a href='function.filemtime'>function.filemtime</a>]: stat failed for config.php

Uninstalled it now but any idea why do I get those errors?

Thanks.

I am still getting this error (a lot) on my Error Log, could anyone help me with this please?

The error message is
----------------------------------------------
/assets/components/smartoptimizer/connector.php : 124) PHP warning: filemtime() [<a href='function.filemtime'>function.filemtime</a>]: stat failed for config.php
----------------------------------------------

Thanks!

just logged a bug report with a fix on github:
https://github.com/omycode/SmartOptimizer/issues/4