The issue with the wood panel showing through the black is due to an RGBA value being used to set the opacity of the background color (black in this case). IE 8 doesn't support RGBA values in backrground colors. The only way around this is to replace the background color with a PNG which is larger than 1x1 pixel and which matches the opacity of black RGBA.

The other issues I can only guess as to what the problem is because I can't see your site. Make sure you have set the background on .mpcalendarothermonth to black and that should work fine in IE 8. If that's how you made it change in FF, then it will work in IE 8. I know you reset cache and tried other computers but make sure you changed the Skin Version Guid in Administration > Advanced Tools > Design Tools > Cache Tool. If you have only pressed the "Disable Cache" button, that will only disable the cache for your account, not everyone else, or even you when you are not logged in to the site.

HTH,
Joe D.

Hi,

You need to create a PNG file which is at least 1x2 pixel and is filled with a translucent black (#000000). Artisteer used 60% (0.6) for Alpha value which means 153 (255×0.6=153). You can download such file here.

Place the file in the images directory of your skin and change

background: rgba(0,0,0,0.6);

on the .art-sheet selector to

background: url('images/rgba-0-0-0-153.png') transparent repeat 0 0;

HTH,
Joe D.