So I'm using PIE.htc from http://css3pie.com/ and using it on a parent element div#page-contents, as well as some elements inside that (dl.mainfeatures, div#login-stuff, etc.). On IE 8 (haven't tested other versions yet), the CSS3 code I use appears just fine on the parent element, but none of the child elements are showing anything (rounded corners, box shadow, nothing). Even regular CSS attributes (background-color, border) aren't showing up.
Is there some issue with applying an HTC fix to child elements and their parent element at the same time? How can I get this to work?
Without any actual example code it's hard to see what the problem actually is.
However you may want to double-check against the list of known issues with CSS3Pie; there are a few. The vast majority of weird glitches with CSS3Pie turn out to be related to position and z-index, so these are the first things to check.
Also, if you really can't solve it, ask on the CSS3Pie forum -- the author is very good at responding to questions. (plus there are a bunch of other posts already there from people asking similar questions, so you may find someone else has already asked the same thing)