Site Dropped From Ranking in a Weird Way

Hi,

I have a coupon site companynameprintablecoupons.com whichh was at #7 for its Keyword.

I built around 400-500 High Pr Signature Profile Link and the site dropped from ranking however its inner pages rank at Page 3-5. Tag Pages rank at PAge 2 however main domain has dropped.

Same happened with my other wesite companynamecouponssite.com However it did have a Sitewide link coming from PR2 website with around 900 links indexed.

Can anyone suggest what shall I Do to get the main domain back in ranking like it did before?

Help Appreciated
Thanks

PM me your domain, I won't compete- I'll try to help you diagnose a problem!