When should we not receive holy communion? As we are all sinners, saved by grace, how do we decide if we should take communion?  As a born again believer we still have times in our lives when we carry a particular sin in our heart or mind or deed.  According Baptists, during those times should we not receive communion?
Most Baptists deny the existence of Venial sins, while at the same time declaring salvation permanent.  Some support for that statement can be found here, though this is far from an authoritative source for all Baptists.  Compiling an authoritative statement of faith on the subject for every Baptist denomination is left as an exercise to the reader.

Nonetheless, as you have shown, there are some requirements Baptists are called to respect when receiving their symbol of Communion.  You can read a discussion of what these requirements entails on the forums here, and I would recommend asking your question there as well as here.  

In essence, Baptists believe only those walking in obedience to God should receive Communion.  Any Baptist who has committed any sin, then, ought to forgo participation in Baptist Communion until such time as they have reconciled themselves of that sin.  This position is a synthesis of what I perceive to be the majority position based on transcripts of discussions amongst various Baptists, but it is far from the only major Baptist position.