Welcome aboard Stepas. I don't know what the ones with underscores are, perhaps someone will enlighten us. I do know the other ones are proprietary, meaning, they are only for specific browsers and not in the spec for the doctype you are using. It's not likely those will ever validate.
I am assuming you are intentionally using underscore hacks to target IE6 and lower only, scrollbar-face-color is not a valid css reference, but an IE specific 'fix', the behaviour file is a fix for IE failing to understand png transparency, DXImageTransform is are also an IE specific 'fix', zoom is a IE specific fix to solve 'hasLayout' issues - you can safely ignore the error about -moz-opacity - that is a completely valid forward compatible extension to css there is no align:center property.
If you want to hide these validation errors from the validator, put them (apart from the -moz-opacity) in an IE conditional comment
Hi there Stepas, the validator does not recognise the completely valid -moz prefix. This is a vendor specific prefix for specifications that are not yet standard. In css3, the property is opacity, because it was not fully standardised, browser vendors are allowed to use vendor prefixes to provide additional functionality. Thus, you can safely ignore this validation error.