The packages conflict with other packages in either Extras or Core. Details following in next comment.
pdftohtml-0.36-7.fc5.i386.rpm File conflict with: /usr/bin/pdftohtml File conflict with: /usr/bin/pdftohtml => Package conflicts with: poppler-utils - 0.5.1-2.i386
Since I can't really rename the binary (it's the name of the tool), I'll just add a Conflicts tag. Thanks for the notice, fixed in CVS.