Dumbledore mystery -- please explain

[kneazelkid]

No: HPFGUIDX 76916

OK I have obvisouly missed somthing. I understand that DD would avoid 
Harry after the whole Arthur-Weasley-snake-incident-combined-with-
possible-V-possession. But why was he avoiding Harry in the first 
half of the book? 
I know this is probably simple and I just missed it but I'm a little 
confused and figured yall could clear me up quickly.
Thanks,
kneazelkid -- who is usually pretty good about these things