I am building Kamailio 3.1.5 on Solaris 10 64bit environment and I am getting this error. yacc -d -b cfg cfg.y "cfg.y", line 104: fatal: invalid escape, or illegal reserved word: expect gmake: *** [cfg.tab.h] Error 1 I tried compiling with bison, but got errors immediately after getting thru the yacc (I just issued ln -s /opt/csw/bin/bison /opt/csw/bin/yacc and recompiled) flex cfg.lex CC (gcc) [kamailio] lex.yy.o In file included from ip_addr.h:50:0, from globals.h:37, from cfg.lex:91: ut.h: In function 'str2s': ut.h:195:17: warning: variable 'init' set but not used [-Wunused-but-set-variable] cfg.lex: In function 'yylex': cfg.lex:561:11: error: 'yylval' undeclared (first use in this function) cfg.lex:561:11: note: each undeclared identifier is reported only once for each function it appears in cfg.lex:561:40: error: 'FORWARD' undeclared (first use in this function) cfg.lex:562:40: error: 'FORWARD_TCP' undeclared (first use in this function) cfg.lex:563:40: error: 'FORWARD_TLS' undeclared (first use in this function) Thanks Nathaniel L Keeling