No error message in error.log

Hi all,

I d'ont have much experience in apache configuration and
administration.
In the error.log I can see messages like

[Mon Aug 20 09:16:23 2007] [error] [client 10.20.30.123] , referer:
http://myserver/scripts/MyApp.exe

Is there no error message between client ip adress and referrer ? In
other logs there messages like 'file not found.....' or something like
this.
The error level is debug !!! How can I find the error code/message for
what is logged here ?
I'm using apache 2.2.4 on windows server 2003 R2 SP 2.

Thanks in advance

Henning