Why has one of my sites PR dropped from 4 to 0

[Sitebee]

I know google have been currently running a Page Rank update but i noticed on one of my sites the pagerank has dropped from 4 to 0

Should i be worried? I mean thats a big drop for me and possibly may have a damaging effect to the site.

 

[Keagle]

Yup. Perhaps they decided you had too few backlinks or soemthing.

 

[uk_kk]

See the link below.
http://freewebspace.net/forums/showthread.php?t=2187466

I lost 4 points to PR0 on one of the domain but it was graped domain and I was expecting it.