SickSquirrel on "Odd entries in 404 logs"

I checked my 404 logs to see if anything was wary. I noticed twto odd entries

/qffmjymbcpj/fffpmgkq/class.class. 3 -- August 31, 2013, 1:40 am

/qffmjymbcpj/fffpmgkq.class. 3 -- August 31, 2013, 1:40 am

That is URL, number of tries, date, time

I checked FTP right away for that directory but nothing on my server . I'm wondering what they are looking for.