Wp-slimstat gives a fatal error

Update #1: I forgot to explain what wp-slimstat is. Wp-slimstat is a simple web statistic wordpress plugin, which means you can see how many visits you get and from where/how many/etc. But the good part is that you can see it when you login there will be an extra tab on the Dashboard to the statistics “Slimstat”.

Update #2: RTFM ….. in the README.txt (chapter 8. LOCALIZATION) there is an explanation about this “fatal error”

make sure you have set your blog’s default language in wp-config.php,
e.g. : “define (‘WPLANG’, ‘en_US’ );�? and that the corresponding
localization file exists in wp/slimstat/lang folder.

I found my error on the wordpress.org support forum… the solution I describe here still works.

Today I tried to install wp-slimstat and all I got:

Fatal error: Cannot instantiate non-existent class: cachedfilereader in [snipped]/wp-includes/wp-l10n.php on line 67

hmmm…
I could not find the answer to this problem on the site of the creator of this wp-plugin but it seems that all wordpress-2.0.4-users have this problem!
So I try good old google …. and found the answer..
http://mu.wordpress.org/forums/topic.php?id=888

try open wp-config.php or wp-config-sample.php
edit this lines:
define ('WPLANG', '');
to
define ('WPLANG', ' ');

And now I have wp-slimstat, so I know what you did last hour!