What do grants have to do with it?

Ok, I know that we are warned that the post that are placed on our blogs can be seen by co-workers.  Will I'm about to go off even if they can see.  Today I sent an email out to the departments grant team informing them that the deadline for competitive grants is approaching fast.  I did this as a courtesy, but you know what they say, "no good deed goes unpunshied".  One of the deputy director's in our department says that he had no idea that these grants were due and that his section has to prepare an application.  I find this hard to believe since I sent him an email last month telling him what staff are available to help him prepare the app.  To futher and insult to injury... He approaches my supervisor and says that I failed to communicate the grant information to him.  I have copies of four (4) seperate emails sent to him and his staff outlining the details of the grants.  Why is it so hard for people to admit when they make a mistake?