the :pseudo class in the selector is tripping up IE8!
you have to ungroup these selectors if you absolutely have to use those CSS3 pseudo classes;
If there's a selector in the ruleset that IE8 doesn't understand it's ignoring the whole thing - this is common in IE8 with CSS3 pseudo classes
e.g. If you separate them out and remove the pseudo :disabled
parts of the selector completely - you'll see the first example below works for all, whereas the second one still works except for IE7
input[disabled], select[disabled], textarea[disabled] {background-color: #0f0;} /* lime green - works in IE7+ and modern browsers */
input[disabled="disabled"], select[disabled="disabled"], textarea[disabled="disabled"] {background-color:#ff0;} /* yellow - IE8+ and modern browsers */
the color (as opposed to background-color) issue pointed at in another answer is not the cause of your issue, but it wouldn't help if you were also trying to change the color ;)