Hi Avati, That might be a problem with 'byacc' and 'bison' compatibility. These were seen at many places with many other packages. Even the 'bison -y' i don't think is fully 'byacc' mode. As you can see after installing bison the error goes away and 'make' is smooth as it has to be. But for having that compatibility check we can add in configure.ac a better check for yylval, and yylex function. Regards & Thanks -- Harshavardhana "Software gets slower faster as Hardware gets faster"