Help, new to film photography and grainy pics

[bkarger]

Hello all, I took a lot of shots this weekend and they all came out grainy. Can someone help me! I have no idea what I am doing wrong. I am using a Canon Rebel EOS 2000 with a 28-80 lens and a 55mm polarizing filter (I know my lingo is not good yet, but I am learning). Should I take off the filter? The film is 400 too and I was using a tripod on many shots.
Can you please offer suggestions.
[img]<a%20href="http://s151.photobucket.com/albums/s129/mnkeygirl/?action=view&current=2970_1119347936703_1017157880_30387.jpg"%20target="_blank"><img%20src="http://i151.photobucket.com/albums/s129/mnkeygirl/2970_1119347936703_1017157880_30387.jpg"%20border="0"%20alt="Photobucket"></a>[/img][img]<a%20href="http://s151.photobucket.com/albums/s129/mnkeygirl/?action=view&current=2970_1119351096782_1017157880_30387.jpg"%20target="_blank"><img%20src="http://i151.photobucket.com/albums/s129/mnkeygirl/2970_1119351096782_1017157880_30387.jpg"%20border="0"%20alt="Photobucket"></a>[/img]

[bkarger]

I found the instructions for posting the pictures so here are a couple (more in my gallery). Note, the 2nd one has not had any touchup work while the 1st one has.

[bkarger]

DO NOT CLICK ON THIS LINK, THERE IS A VIRUS ATTACHED. LUCKILY MY COMPUTER FOUND IT 1ST.