When I try to install PPerl in my local lib folder '/opt/lib' make is failing. Here are the steps I followed. perl Makefile.PL PREFIX=/opt/lib make and I get this error main.c: In function `DispatchCall': main.c:421: `LOCK_EX' undeclared (first use in this function) main.c:421: (Each undeclared identifier is reported only once main.c:421: for each function it appears in.) main.c:421: `LOCK_NB' undeclared (first use in this function) main.c:572: `LOCK_UN' undeclared (first use in this function) make: *** [main.o] Error 1 Am I doing something wrong. Can you provide some guidance in Installing this module. Please let me know if I need to provide more detail. Thanks in advance for your help. Thanks Prakash