http://jigsaw.w3.org/css-validator/validator?text=.recenttitle%7Bfilter%
3Aprogid%3ADXImageTransform.Microsoft.Gradient%28GradientType%3D1%
2C+StartColorStr%3D%27%23FF003399%27%2C+EndColorStr%3D%27%23FF6699CC%27%29%
3Bpadding-left%3A8px%3B%7D&warning=1&profile=css2&usermedium=all&output=soap12

or

.recenttitle{
  filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=1, 
StartColorStr='#FF003399', EndColorStr='#FF6699CC');
  padding-left:8px;
}

generates

<m:error>
<m:line>
0</m:line>
<m:errortype><m:errorsubtype>unrecognized</m:errorsubtype>
<m:skippedstring>:8px;}</m:skippedstring>
</m:error>

which ain't well-formed, missing </m:errortype>.