You may need to install the yacc package, as root type urpmi yacc then press enter, if your sources are set this will download and install the yacc package. If your sources are not set I recommend going here http://easyurpmi.zarb.org/
follow the onscreen instructions. When all is done attempt the above urpmi again. You could of course install the yacc package from your Mandrake CD, but setting your sources as instructed by the above url gives you access to loads more software, libraries, updates etc.