Strange warnings in log file (location: http:///*, hostname: ::1)

I get a lot of warnings like the one below:

Type	page not found
Date	Wednesday, November 18, 2009 - 13:22
User	Anonymous
Location	http:///*
Referrer	
Message	*
Severity	warning
Hostname	::1
Operations	

Any idea where this might come from or how to avoid this?

Thanks,
Hendrik.