Imp problems - Help me please

[Roberto Samarone Araujo (RSA)]

Since two weeks ago, I'm trying to install IMP (I think it's the best
Webmail) but, I'm having some problems ... Now when I try to enter the
webmail it show me the message :

            Fatal error: Call to indefined function: shm_attach() in
/usr/local/phplib/ct_shm.inc

        Someone tell me that I need to install PHP 4 with shared memory
support but, I can I do this ?

                                thanks,

                Roberto Samarone Araujo